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THE BOYS' BOOK 
OF ENGINE-BUILDING 




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THE BOYS' BOOK 
OF ENGINE-BUILDING 

HOW TO MAKE STEAM, HOT AIR AND GAS 
ENGINES AND HOW THEY WORK, TOLD IN 
SIMPLE LANGUAGE AND BY CLEAR PICTURES 



BY 

A. FREDERICK ROLLINS 

Author of "Design and Construction of Induction Coils," 
"Manual of Wireless," "Keeping Up with Your 
Motor Car," "How to Fly," "The Book of 
Wireless," "Shooting for Boys," "In- 
venting for Boys," etc. 



With Drawings by the Author 




BOSTON 

SMALL, MAYNARD AND COMPANY 

PUBLISHERS 



.C6 



Copyright, 1918 

By SMALL, MAYNARD & COMPANY 
(incorporated) 



may 21 1918 



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©CI.A499047 






A WORD TO YOU 

I hope you will read these few pages about a 
boy who built model engines along in the late 7o's 
out in the Far West and at a time when and a 
place where it was next to impossible to get ma- 
terials for his work. 

This boy was Bion J. Arnold, now our fore- 
most American engineer. He was only thirteen 
years old when he built his first engine — and it 
worked, too. It was a little horizontal steam 
affair about seven inches long, and he went about 
building it in the right way — that is he made 
patterns for the chief parts, cast them in lead 
and put them together with the tools of a kindly 
disposed gunsmith. 

When Bion was fourteen, he built a vertical 
steam engine over a foot high and here is where 
his genius showed itself again, for he used a piece 
of old iron pipe for the boiler, a discarded hub 
from a wagon wheel for the fire-box, a wheel 
from a valve, which had been thrown away, for 



A Word to You 

the flywheel, a gas-cock some one had given him 
for the throttle valve and, finally, he riveted the 
fire-box to the boiler with bolts which he had 
forged with his own hands. 

He built his third engine when he was fifteen ; 
the main parts of this he cast in Babbitt metal 
and he made the boiler of % inch thick sheet iron 
which he hammered into shape and riveted to- 
gether at the forge of a genial blacksmith. The 
heads of this boiler were made of two wooden 
disks and these were tied in place by passing four 
iron rods through them and held on with a couple 
of nuts. 

His next attempt was made when he was six- 
teen years old. His idea was to build a 2 horse 
power engine to drive the wood saw with — a 
noble scheme since it was his job to keep enough 
wood in the box for the kitchen fire — but his 
father would have none of either the scheme or 
the engine and so both were scraped somewhere 
between the time it was concocted and the place 
where it would have been put to work. 

Having been so successful in building these 
small model engines young Arnold began his last 
model when he was seventeen, and this was a 



A Word to You 

miniature locomotive of the type that was in com- 
mon use on western railroads in 1876, and for 
about ten years thereafter. A picture of his 
handiwork is shown in the frontispiece of this 
book. 

He took the measurements for it from the big 
locomotives in the roundhouse at Lincoln, Ne- 
braska, where he was going to school and, with 
his father financing his hobby, after many months 
of hard work he finished his model engine. 

It is complete down to the smallest details, if 
we except the air brakes and the air compressor 
for it, but even these were made though he never 
put them on. This beautiful little model — it is 
three feet long — can be seen in Mr. Arnold's 
Chicago office where the master builder now con- 
ceives and directs various kinds of engineering 
work on a gigantic scale. 

When the model locomotive was fired up with 
real coal and a few pounds of steam were raised 
in the boiler, it ran as smoothly as any of its big 
prototypes, much to the pleasure of the builder 
and the delight of those who saw it in operation. 

Now the point is this: To build a working 
engine however small takes a certain amount of 



A Word to You 

mechanical ability plus stick-to-it-ive-ness, and if 
you have these qualities there isn't a reason in 
the world why you should not become a great 
engineer — not so great, perhaps, as Mr. Arnold, 
for his income now as a traction engineer is con- 
siderably more than that of the President of the 
United States. 

If it is your intention to become a civil, me- 
chanical or an electrical engineer — Mr. Arnold is 
all three — the thing for you to do is to learn how 
to use tools as well as a mechanic does and then 
you want to get the best technical schooling you 
can. 

With this equipment, provided you have a fair 
amount of business tact too, you will be assured 
of a large income as long as you live. And this 
is why you should start in now and build engines. 

A. Frederick Collins. 

550 Riverside Drive, 
New York City. 



CONTENTS 

CHAPTER PAGE 

I. — The First Engines I 

II. — Two Simple Steam Turbine Engines . . 24 

III. — A Simple Piston Steam Engine ... 45 

IV. — A %4-H. P. Horizontal Steam Engine . 61 

V. — Making Small Boilers 91 

VI. — Fittings for Model Engines . . . .110 

VII. — A Model Atlantic Type Locomotive . .138 

VIII. — A Model Atlantic Type Locomotive 

(Con.) 156 

IX. — Steam, the Giant Power 182 

X. — A Hot Air, or Caloric, Engine .... 199 

XL— A y s -H. P. Gas Engine 214 

XII. — Useful Information ....... 241 

Appendices 247 



THE BOYS 5 BOOK OF 
ENGINE-BUILDING 

CHAPTER I 

THE FIRST ENGINES 

Hero Invents the Steam Engine — Branca Devises a 
New Engine — Papin Gets up the Piston Engine — New- 
comen Makes the Engine Work — The Boy Who Made it 
Self Acting — Watt Puts on the Flywheel — The Develop- 
ment of the Steam Boiler — The First Steamboats — The 
Invention of the Locomotive — The Modern Steam Tur- 
bine — Some Other Kinds of Engines : The Compressed 
Air Engine; The Hot Air Engine; The Gas Engine. 

About the beginning of the Christian era, a 
babe named Hero first saw the light of day in far 
off Alexandria in Egypt, and this child was des- 
tined to make a lasting impression on the human 
race. 

Even as a boy he built apparatus and machines 
of all kinds, even as you do now, but this was 
doubly hard in his day for few inventions had 



2 The Boys' Book of Engine-Building 

been made and tools to make them with were just 
about as scarce, for science had not yet come into 
its own. 

Hero Invents the Steam Engine.— But Hero 
was not discouraged and he began to invent and 
make things for himself. To tell you of all the 
experiments he made and all the apparatus he 
built would take a whole book of this size, but 
his greatest invention and the one that interests 
us now is his steam engine, for he was the first 
who ever made steam do useful work. 

Hero called the steam engine which he invented 
and built an eolipile (pronounced a-ol'-i-piV) and 
this curious word he coined from two Latin 
words, the first of which is Eolus, the name of the 
god of the winds, and the other one pila, which 
means ball. 

Let's find out now just why Hero named 
his engine the god of the winds plus a ball ? In 
the first place he made his engine of a hollow 
metal ball ana he fitted two short bent pipes into 
holes on the opposite sides of it. Next he 
mounted the ball on a pair of hollow pipes, or 
trunnions as they are called, so that it would re- 
volve easily and the lower ends of these pipes 



The First Engines 3 

were fixed to a boiler, all of which is shown in 
Fig. 1. 

When he built a fire under the boiler the steam 
passed through the trunnion pipes into the ball 
and then out of the bent pipes into the air. As 
the steam struck the air with considerable force 




Fig. 1. Hero's Reaction Engine or Eolipile 



it acted much the same as a rubber ball does when 
it strikes a sidewalk, that is it reacted on the hol- 
low ball forcing it to turn in the opposite di- 
rection and at a fairly high speed, like unto the 
winds let loose by the god Eolus. This is the 
reason an engine of this kind is called a re-action 
engine. 

Branca Devises a New Engine. — Strangely 
enough nothing more worth while was done in 



4 The Boys' Book of Engine-Building 

the way of transforming the energy of steam into 
mechanical motion during all the long centuries 
from the year i to 1609. 

Then an Italian named Branca devised another 
sort of rotary steam engine. He made a paddle- 
wheel and when the steam from a boiler was 
directed through a spout, or more properly a 




Fig. 2. Branca' s Impulse Engine or Turbine 

nozzle, against the paddles, or blades, as shown in 
Fig. 2, the force of the impulses of the steam 
striking them made the wheel revolve. For this 
reason an engine of this kind is called an impulse 
engine. 

In those early days the Italians put an artistic 
touch on everything they made — indeed they 
haven't got over the habit yet — and so it was per- 






The First Engines 5 

fectly natural for Branca to give his boiler the 
head and body of a human being and he added 
to the life-like effect by having the steam blown 
from its mouth. 

Now you may think out loud that a reaction 
ball like Hero's or an impulse wheel like Branca's 
is not a real steam engine but if you do you are 
quite mistaken for it so happened that within the 
last twenty years both of these ancient toys have 
led to the last word in steam engine building and 
that is — the steam turbine. 

Papin Gets Up the Piston Engine. — The first 
steam engine in which steam in a cylinder moved 
a piston forth and back, or up and down, came 
shortly before Branca devised his rotary engine 
but these engines were used only for pumping 
water, for no one knew how to change the re- 
ciprocating motion, as the to and fro motion of 
the piston is called, into rotary motion, as the 
complete turning of a wheel is called, for another 
hundred years or so. 

To begin at the beginning of the first invention 
of the piston engine, we have to start with Den- 
nis Papin, a Frenchman. In 1610 he got up the 
scheme of using a piston in a cylinder and moving 



6 The Boys 9 Book of Engine-Building 

it by steam ; I say scheme because it did not work 
successfully when he built it. The trouble with 
his engine was that he made the boiler and the 
cylinder in one piece. 

The way he tried to use it was to pour a little 
water in the bottom of the cylinder, which stood 
in a vertical position. Then he heated it as 
shown in Fig. 3. When steam was made it 




Fig. 3. Papin's; The First Piston Engine 

forced the piston up, the fire was then taken 
away, the steam cooled down, thus forming a 
vacuum in the cylinder, and the pressure of the 
air on the piston forced it down again. 

Although this engine of Papin's was intended 
to work half by steam and half by air pressure it 
was called an atmospheric engine and this is the 
name it has always been known by. 



The First Engines 7 

Newcomen Makes the Engine Work. — 

Nearly a hundred years later, in 1705, Thomas 
Newcomen, of England, and his assistant, James 
Cawley, made the piston engine of Papin work. 
They accomplished this by using a boiler that 




Fig. 4. Newcomers Improved Engine 

was separate and distinct from the cylinder. 
The piston in the cylinder was connected by a 
rod to one end of a lever called a walking beam 
and a weight to balance it was hung on the other 
end of the beam as shown in Fig. 4. 

When steam was admitted into the cylinder 
from the boiler, it forced the piston up, then the 



8 The Boys' Book of Engine-Building 

steam valve was shut off and a little cold water 
was let into the cylinder to condense the steam, 
that is to change it into water again, when a 
vacuum would be formed; this done, the piston 
was pushed down by the pressure of the air on 
it; when the steam was turned into the cylinder 
again, it forced the water out through another 
valve. 

The end of the walking beam which carried 
the weight was connected to a pump and hence 
the Newcomen engine came to be largely used in 
England for pumping water out of mines. 

The Boy Who Made It Self-Acting. — As you 
can imagine the piston of Newcomen's engine 
worked very slowly and the steam and water 
valves had to be opened and closed by hand. As 
it was light, though tedious, work to do this, a 
boy was usually given the job and a youngster 
named Humphrey Potter happened to be one of 
them. 

Now Humphrey was a boy of genius, and 
genius and humdrum work are seldom on speak- 
ing terms. So he bethought him to rig up some 
levers worked by strings tied to the walking 
beam to open and close the valves and his inven- 



The First Engines 9 

tion worked like a charm. He was in a fair way, 
at least it seemed so to him, to draw his sixpence 
a day while the engine worked automatically. 

Instead his genius threw himself and all the 
other valve boys in England out of their jobs, and 
all he ever got out of it was undying fame. 




Fig. 5. Potter's Self-Acting Engine 



Humphrey's invention was at once improved 
upon by one Henry Beighton who connected a 
rod to the walking beam to work the valves and 
it is quite likely that, being a man, he profited 
by it. 

Watt Puts on the Flywheel. — In your young 



io The Boys 9 Book of Engine-Building 

lifetime you have heard enough of James Watt, 
of Glasgow, Scotland, to believe, probably, that 
he was the inventor of the steam engine, but you 
have seen that Papin and Newcomen and Potter 




Fig. 6. Watt's ; The First Real Engine 



developed it to a considerable extent before Watt 
took it up. 

What Watt did, though, constituted a mighty 
invention for it was he who made the wheels 



The First Engines II 

go round. It was in 1763 that he conceived the 
idea of connecting the piston rod to a crank hav- 
ing a flywheel fixed to it, and this made the engine 
useful for producing power for a thousand dif- 
ferent purposes where before it was limited to 
pumping water. It is shown in Fig. 6. 

To make the piston turn a crank the steam 
had to act on it much faster than it did in the 
Newcomen engine, so Watt let the steam escape 
from the cylinder at the end of each stroke, in- 
stead of condensing it in the cylinder by letting 
water run into it. Not only this, but by keeping 
the cylinder hot the engine used far less steam, 
and so it was much more economical. 

Some years after Watt made two other im- 
provements of great value, first of which was to 
admit steam on each side of the piston alter- 
nately, thus making the engine double acting; and 
the second was to cut off the supply of steam to 
the cylinder before the piston had completed its 
stroke and so using the expansive power of the 
steam in the cylinder to force the piston on to the 
end of its stroke. 

Finally, Watt invented the throttle valve, so 
that the amount of steam which flowed into the 



12 The Boys' Book of Engine-Building 

cylinder could be controlled ; and he also invented 
the centrifugal governor which opens and closes 
the throttle valve automatically, depending on 
the speed with which it revolves and this in turn 
regulates the speed of the engine. 

The Development of the Steam Boiler. — 
Since the first engine was the one built by Hero, 
we are bound to believe that the first steam boiler 
was the one which he used to generate steam for 
it. His boiler, as shown in Fig. i, was simply 
a hemispherical shell set on a stand and heated 
by a fire under it. 

In the early days of the piston engine boilers 
were built in the shape of long boxes with fires 
under their entire length, but they were so weak 
that a steam pressure of only three or four 
pounds to the square inch could be used with 
safety. For this reason cylindrical boilers, which 
were very much stronger, took the place of the 
rectangular boilers. 

The greatest improvement in boiler making 
came, however, when some genius put a central 
Hue in it and fixed the open ends to the boiler 
heads, or sheets, as they are called, so that there 
is a hole clear through the middle of the boiler. 



The First Engines 



13 



This is surrounded by water and the heat of the 
fire passes through it, as shown in Fig. 7. 
As this scheme proved so successful, a large 




Fig. 7. The Fire-Tube Boiler 

number of fire tubes, as these flues are called, 
were then used for they gave a larger heating 
surface and, hence, a higher pressure could be 



14 The Boys' Book of Engine-Building 

kept up. The tubular boiler, as this type is 
known, see Fig. 8, is largely used for stationary 
engines and is the only kind used for locomotives. 
The First Steamboats. — Long before a steam 
engine capable of doing useful work had been 
invented, men began to think about using steam 
to propel boats. 



Fig. 8. A Modern Tubular Boiler 

The first boat actually driven by a steam en- 
gine was a packet built by John Fitch, of Eng- 
land, in 1787. It was a pretty crude attempt, for 
it used paddles at the sides and these were moved 
with a feathering stroke very like that used 
when you paddle a canoe. It ran at a speed of 
about three miles an hour. 

Fitch built another steamboat moved by paddles 
at the stern, but his third boat was a great im- 



The First Engines 15 

provement over the other two, for it was driven 
by a small propeller. From 1785 to 1788 Miller 
and Symington, also of England, experimented 
with a steam propelled pleasure boat, but their 
efforts did not lead to any practical results. 

In 1803 Robert Fulton, of your own United 
States, was in Paris and while there built a small 




Fig. 9. Fulton's Steamboat the Clermont 

steamboat and operated it on the Seine with 
great success. Coming to America he built the 
Clermont, in 1807, a small paddle-wheel packet, 
a picture of which is shown in Fig. 9, and 
launched her on the Hudson River. 

When she started on her trial trip from New 
York to Albany, thousands of eager spectators 
lined the shore and marveled at the ease and 



16 The Boys' Book of Engine-Building 

speed with which she sailed up the river. She 
reached Albany without mishap and thus it was 
the great era of steamboats and steamships be- 
gan. 

The Invention of the Locomotive. — The first 
locomotive built was really a steam automobile, 
that is it was made to run on ordinary roads. 

Since the engines were poor and the roads were 
bad, Richard Trevithick, of England, built a 
locomotive in 1804 to run on a track. Being 
fearful that the wheels would slip on the smooth 
surface of the rails he used a cog wheel that 
meshed with a cog rail. 

Matthew Murray, also of England, built the 
next locomotive in 181 1. It had two upright 
cylinders set on top of the boiler ; the piston rods 
were connected with a crankshaft, and a wheel 
on this turned the driving wheels. The first en- 
gine to use a fire tube boiler was made in 1813 
by William Hedley, likewise of England, and his 
engine was also the first to make the spent steam 
from the cylinders exhaust through the smoke- 
stack to give the furnace a good draft. 

It was George Stephenson — he was of England 
too — who put the finishing touches on the loco- 



The First Engines 



17 



motive in 181 4. This he did by connecting the 
piston rods directly to the crank pins on the 
driving wheels and he linked the front and back 
driving wheels with a coupling rod. 

Stephenson built the Rocket in 1829, see Fig. 




Fig. 10. Stephenson's Locomotive, The Rocket 

10, and in a test on the Liverpool and Manchester 
Railway it ran away from its competitors, all of 
which were driven by sprocket wheels and chains. 
He not only won the prize, but fixed the design 
for locomotives from that day to this. 

The Modern Steam Turbine. — And now we 
come back to the place where we started from 



1 8 The Boys 9 Book of Engine-Building 

2000 years ago, which goes to prove the truth of 
the saying, "The first shall be last/' Engineers 
of our own time have perfected the reaction 
engine of Hero and the impulse engine of Branca 
and by combining the principles of both they 
have made an engine which uses far less steam 
and is much smaller for the horse power devel- 
oped than the best reciprocating engines now in 
use. It is not called a steam engine, however, 
but a steam turbine if you please, though it is an 
engine just the same. 

Though other men had built steam turbines, 
it was Gustav De Laval, of Sweden, who, in 
1883, made it a practical success. He did this 
by driving a cream separator with it. His tur- 
bine is a highly developed Branca' s impulse en- 
gine having a single wheel mounted on a flexible 
shaft. The small ones run at the enormously 
high speed of 30,000 revolutions per minute and 
this is slowed down to working speeds by means 
of what are called reduction gears. It is shown 
in Fig. 11. 

A year after De Laval got out his single wheel 
turbine, Charles A. Parsons, of England, com- 
bined the principles of the reaction and impulse 



The First Engines 



19 



engines and built the first multiple steam turbine. 
This turbine, see Fig. 12, developed 10 horse 
power when running at 18,000 revolutions per 




Fig. 11. De Laval's, the First Practical Turbine 

minute and its success led to the building of 
steam turbines powerful enough to drive the 




Fig. 12. Parsons', the First Multiple Turbine 

largest steamships across the Atlantic Ocean in 
less than five days. 

Other Kinds of Engines. — There are several 



20 The Boys' Book of Engine-Building 

other ways to run engines besides using steam. 
Among them are by (i) compressed air; (2) hot 
air and (3) gas, or gasoline, which amounts to 
the same thing. 

The Compressed Air Engine. — Any kind of an 
engine that can be run by steam can be run by 
compressed air. A simple way to compress air 
for running a small engine is described in Chap- 
ter V. 

Compressed air is used instead of steam for 
running large engines when (a) the source of 
power must be a long way off from the engine; 
(b) when the smoke is objectionable as on street 
cars and in submarines, and (c) where the heat 
from the fire-box is dangerous, as in mines. 

The Hot Air Engine. — The hot-air, or caloric 
engine as it is sometimes called, is so built that 
the heat of the fire is used to produce mechanical 
motion by acting directly on the piston. 

This kind of an engine was invented by Robert 
Stirling, of England, in 181 6 and in 1827 he built 
his first practical engine. John Ericsson, of 
Sweden, made an improved hot-air engine in 
1833, but it was not until 1852 that he built his 
first commercial engine, see Fig. 13, and engines 



The First Engines 



21 



of this type are largely in use at the present time 
for pumping water. 

The Gas Engine. — In this engine a fuel gas, 
such as coal gas, or a gas formed of gasoline, 
mixed with air, is drawn into the cylinder and, 




Fig. 13. Ericsson's Hot Air Engine 

after it is compressed by the piston, is exploded 
usually by a hot tube, or an electric spark, which 
produces what is called the power stroke. 

The beginning of the gas engine dates back to 
1678 when the Abbe d'Hautefeuille, of France, 
conceived the idea of using the explosive power 
of gunpowder on a piston to make it do work. 



22 The Boys' Book of Engine-Building 

Philip Lebon, also of France, patented an engine 
in which he proposed to use coal gas as the ex- 
plosive fuel. 

The first gas engine that actually worked was 
invented by Lenoir, likewise of France, in i860. 
He used gas for the fuel and this was exploded 




Fig. 14. Otto's Gas Engine 



by an electric spark, but since the gas was ex- 
ploded without being compressed, his engine was 
very wasteful and inefficient. 

To Dr. Otto, of Germany, belongs the credit 
of having brought the gas engine to a successful 
conclusion in 1878. This was done by drawing 



The First Engines 23 

in the gas on the suction stroke, compressing it 
on the compression stroke, exploding it to pro- 
duce the power stroke and exhausting the burnt 
gases on the exhaust stroke. Hence this kind of 
a gas engine is known as the Otto four cycle 
engine and to its development is due not only the 
automobile, but that mightier marvel, the air- 
plane. 



CHAPTER II 

TWO SIMPLE STEAM TURBINE ENGINES 

Making the Boiler — Forming the Turbine Wheel — An 
Easily Made Alcohol Lamp — Running the Turbine — A 
Model De Laval Turbine — The Tools Required — Making 
the Turbine Wheel — Forming the Blades — Fashioning 
the Nozzle — The Turbine Wheel Case — The Bearings 
for the Shaft — Mounting the Wheel — The Reduction 
Gears — How the Steam Turbine Works: The Action 
of the Blades ; How the Nozzle Works. 

A Simple Steam Turbine Engine. — Just as 
hundreds of other fellows before you, from 
Branca to the present time, have built impulse 
steam engines for their first models, so you would 
do well to follow in their footsteps and make one 
too. 

To make a toy paddlewheel engine, or turbine, 
as it is now called, is a matter of a couple of 
hours' work and it will give you many times that 
many hours' pleasure, for steam in action is a 
wonderful power and what is equally to the point 
it has done more to make our world a cheerful 

24 



Two Simple Steam Turbine Engines 2$ 

place to live in than any other power harnessed 
by man, not even excepting electricity. 

Now there are two chief parts to every steam 
power plant, however small or large as you have 
had occasion to observe in the first chapter, and 
there are, (i) the boiler which generates the 
steam and (2) the engine which transforms the 
energy of the steam into rotary mechanical mo- 
tion, which means in everyday English that the 
force of it turns a wheel around. 

Making the Boiler. — To make this little steam 
turbine get a /4 pound baking-powder can — 
empty of course — and soak it in water until 
the paper label comes off; this is for the boiler. 

Drill or punch a %-inch hole in the can for the 
nozzle, about i/4 inches back from the open end 
and drill or punch four /46-inch holes, two on 
each side, at the places shown in the side and end 
views in Figs. 15 and 16 for the rivets; and, 
finally, cut a %-inch hole in the cover for the 
-filler, that is the hole through which water is 
poured into the boiler. 

For the nozzle get a %-inch piece of brass or 
copper tube, if possible, V% inch long, or make one 
of tin, if necessary, and flatten one end a little. 



P/JDDLE WHEEL 




7X-, CORK IN 
LJ— FILLER 



HOLE 



SOLDER 
COVER 



WIRE 
FRAME TO 

HOLD 
BOILER. 



■ALCOHOL 



Fig. 15. Side View of Turbine 



26 



Two Simple Steam Turbine Engines 27 

Now solder the nozzle over the %-inch hole in 
the can and don't be afraid of using too much 
solder. 

Cut out two strips of sheet brass, copper or 
heavy tin V2 inch wide and 2 inches long for the 
supports that hold the wheel, and rivet these to 
the can so that they will be %-inch apart. You 
can buy small rivets or make them yourself by 
cutting off bits of copper wire. When you have 
these things done, solder the cover on tight. 

Forming the Turbine Wheel. — Next make the 
turbine wheel. Get, or saw out, a wood wheel 
V2 inch thick and about 1 inch in diameter, or if 
you can get a spool, on which ribbon is wound, of 
the right size it will serve the purpose very well. 

Saw 16 slots Vs inch deep at equal distances 
apart around the periphery, that is the rim of 
the wheel, and cut out as many pieces of tin V2 
inch wide and V2 inch long for the paddles, or 
blades, or buckets, as these members are vari- 
ously called. Fix the blades into the slots, using 
sealing wax on the edges, if needs be, to keep 
them in tight. 

Use a piece of perfectly straight iron or brass 
wire, or a wire nail will do, Vs inch in diameter 



wtfstfm 



SPINDLE 



RIVETS 



P/tDDLE WHEEL 
WASHER. 
PULLEY 

SUPPORT 

NOZZLE 

RIVETS 




WIRE 
ERME 



Fig. 16. End View of Turbine 



38 



Two Simple Steam Turbine Engines 29 

and 1% inches long for the spindle, and push it 
through the hole in the wheel; be sure that it 
fits tight and sets absolutely true and be careful 
not to bend the blades. 

Slip a washer over each end of the spindle up 
close to the wheel and then spring the supports 
apart slightly when you can slip the spindle into 
the holes in them with the wheel between. Fix 
a V-shaped pulley to one end of the spindle and 
the hardest part of your job is done. Make a 
frame of wire, shaping it as shown in Figs. 15 
and 16, and make it high enough to hold the 
boiler — it is no longer a baking powder can — 
about three inches away from the surface it sets 
on. 

An Easily Made Alcohol Lamp. — You can 
make an alcohol lamp without any expense by 
using an ink bottle; get a squat one, not more 
than 2 inches high, if you can, though any kind 
will do. Fit a %-inch tin tube in a hole in the 
cork and put a cotton wick in it ; half-fill the bottle 
with alcohol, put the cork in it and you have a 
serviceable lamp. 

Running the Turbine.— YidXi-hM the boiler 
with clean water and cork up the filler hole tight. 



30 The Boys' Book of Engine-Building 



Set the boiler and wheel on the frame, light the 
lamp and set it underneath. The boiler will 
commence to generate steam in five or ten min- 
utes and, when the pressure is great enough, the 
steam will be projected from the nozzle against 



PADDLE 
WHEEL 




FLAME 

WICK 

TIN TUBE 

WIREFRAME 
TO HOLD 
BOILER. 

-ALCOHOL 



Fig. 17. The Steam Turbine Complete 

the blades and the force of it as it strikes them 
will drive the wheel around at a great rate of 
speed. The completed turbine is shown in Fig. 

17. 
A Model De Laval Steam Turbine. — A real 



Two Simple Steam Turbine Engines 3 1 

De Laval turbine has curved blades, a special 
shaped nozzle and a flexible shaft. 

The model turbine which I shall describe has 
curved blades and a regular De Laval nozzle but 
the flexible shaft need not be made. Since this 
turbine will run at a high rate of speed the wheel 
carrying the blades must be very accurately bal- 
anced and while you can make such a wheel if 




Fig. 1 8. A Toy Gyroscope 

you are a pretty good mechanic, I will tell you an 
easier way to get one. 

You can buy a toy gyroscope x like the one 
shown in Fig. 18 for 25 cents. The lead wheel 
in the ring bearing runs very true consid- 
ering its small cost and you would have hard 
work to make as perfectly a balanced wheel. 

1 A gyroscope of this kind can be bought of the E. J. Horsman 
Company, n Union Square, New York City. 



32 The Boys' Book of Engine-Building 

The Tools You Need. — To make this turbine 
you need (a) a small machinist's hammer, (b) 
a pair of tinner's shears, (c) a jeweler's saw 
frame and saws, (d) a drill stock and drills, (e) 
a set of taps and dies for cutting screw threads, 
(f) a jeweller's soldering copper, (g) a couple 
of files, (h) a pair of compasses for dividing 
off spaces and scribing circles, and (i) a needle 
reamer for making tapering holes. 

Making the Turbine Wheel. — To make this 
turbine so that it will be efficient is a harder task 
than to make any other kind of an engine and 
my advice is not to start unless you have lots of 
patience and are willing to work painstakingly. 

Begin by taking the wheel shaft of the gyro- 
scope out of its ring bearing and from this mo- 
ment on be more than careful not to bend the 
shaft, dent the wheel or to mar either one of 
them, for if you do the wheel will never run true 
again. 

Take your compasses and draw a circle on a 
sheet of paper exactly the size of the gyro wheel 
and divide it into equal divisions % inch apart, 
or as nearly as you can and still make them come 
out even as shown at A in Fig. 19. Glue this 



Two Simple Steam Turbine Engines 33 

paper pattern, or template as it is called, on the 
wheel and place one end of the shaft between a 
couple of pieces of sheet lead and then screw it 
up in your vise; the purpose of the lead is to 
keep the rough surfaces of the jaws of the vise 
from marring the shaft. 

Put a saw blade in your jeweler's saw frame 
and use a blade that is the same thickness as that 
of the sheet tin, or brass, you intend to use for 
the blades of the turbine wheel. Saw a slot %e 
inch deep in the rim on each line of the paper 
and be sure to saw each slot straight across the 
rim of the wheel and straight down on the line of 
the paper so that each one will be in a radial 
line with the center of the wheel. 

Forming the Blades. — Having sawed the slots 
in the wheel, the next thing is to make the blades. 
If the wheel of your gyro is 2% inches in diam- 
eter, which is the usual size, the circumference 
of the wheel will be about 8% inches, and since 
the blades are to be set % inch apart there will, 
of course, be 35 blades. 

The blades should be made of sheet brass about 
%o inch thick and all of them must be as nearly 
alike as you can make them. Make each blade 



/v 



34 The Boys' Book of Engine-Building 

% inch wide and cut out the corners to form a 
shank % inch wide and %e inch high as shown in 
the drawing at B, Fig. 19. 

File up all the blades nice and smooth and 



1 



Kn 




Fig. 19. Construction of the Turbine Wheel 



then bend them into the shape shown at C. 
To do this get a piece of iron rod /4 inch in diam- 
eter and 3 or 4 inches long; file out a half-round 
groove in a piece of brass or iron until it fits the 



Two Simple Steam Turbine Engines 35 

% inch iron rod exactly. Lay the grooved form 
on a solid surface, place a flat blade on it, hold 
the iron rod over it, give the latter a sharp tap 
with your hammer and the blade will be bent to 
the proper shape. 

Next set the shank of each blade in a slot in 
the wheel and it should fit in tight. To hold the 
blades in place a rim must be fitted around them ; 
this can be made by cutting a strip of brass % 
inch wide and V2 inch longer than the circum- 
ference of the wheel with the blades set in it; 
file down both ends of the strip so that when they 
are lapped over the joint will have the same thick- 
ness as the rest of the ring. 

To hold the ring in place on the blades while 
they are being soldered to it twist a wire around 
it; then moisten the joint and the tip of each 
blade where it touches the ring with some solder- 
ing fluid. It would be too hard a job to solder 
each one of the blade tips to the ring with a 
soldering copper, but you can do it easily and 
neatly this way : melt one-half a pound of solder 
in a small shallow pan, dip the rim of the wheel 
in the solder and turn it slowly around. By so 
doing the solder will flow evenly and stick to 



36 The Boys' Book of Engine-Building 

those parts where the soldering fluid has 
acted. 

Fashioning the Nozzle. — The nozzle of a De 
Laval steam turbine is of special design, as will 
be explained presently. 

To fashion the nozzle get a piece of brass rod 
% inch in diameter and 2 inches long. Drill, or 
have a machinist drill, a Vi 6-inch hole through 
the center of the rod to within % inch of the 
other end; ream out the hole with a needle 
reamer 1 until the throat is %2 inch in diameter 
and the outlet is % inch in diameter. This done, 
drill out the other end of the brass rod for the 
intake of the nozzle with a %-inch drill to a depth 
of /4 inch, when it will meet the small end of the 
hole which forms the throat. 

Saw off the other end of the nozzle at an angle 
of 15 degrees, as shown in the cross-section view 
A in Fig. 20, and the phantom view at B; this 
will make the outlet, or hole, for the steam to be 
thrown on the blades an ellipse which measures 
% inch wide and % inch long. File the end 
smooth and have a machinist or a steam-fitter 
thread one end of it and screw a standard sized 

1 A thin, round tool for enlarging and tapering holes. 



Two Simple Steam Turbine Engines 37 

union, that is a pipe coupling, on to it so that it 
can be joined to the supply pipe of the boiler. 
This completes the nozzle. 

The Turbine Wheel Case. — The wheel can be 
left exposed and the nozzle mounted on a sup- 
port, but it is better to enclose it so that the ex- 

\% — * 




^45? 




QtmMT 



THROAT 

Fig. 20. Construction of the Turbine Nozzle 

haust steam can be piped away from it. A metal 
case or housing as it is called, can be made by 
cutting out two metal plates Vw or % inch thick 
and 4% inches wide and high and rounding the 
upper halves as shown at A in the side view, 
Fig. 21. 

Clamp these plates together, or screw them up 



38 The Boys' Book of Engine-Building 

in your vise, and drill three /4-inch holes, one in 
each corner and one at the top, as shown by the 
small dotted circles. Next drill a /4-inch hole 
exactly in the center of both plates for the shaft. 
In one of the plates drill three %-inch holes in a 
line so that they just meet and have the middle 
one i/4 inches above the center, or shaft, hole; 
file these holes out with a small half-round file 
so that the beveled end of the nozzle will fit snugly 
into it at the angle shown at B in Fig. 21 and 
solder it there. 

Brace the nozzle with a twisted plate formed 
of a strip of brass Vie inch thick, % inch wide 
and about 1% inches long; drill a %-inch hole in 
one end ; cut a slit on each side of it /4 inch deep 
half way between the ends, and then twist them 
at right angles to each other as shown at C in 
Fig. 21. Slip the end with the hole in it over the 
nozzle and solder the other end to the case plate 
as shown at A. 

Drill a /4-inch hole near the lower side of the 
other case plate for the exhausts, and this ought 
to have a pipe soldered to it. Finally, get three 
6-32 brass machine screws 1 inch long with a 
washer and a nut on each one, also get a piece 



Two Simple Steam Turbine Engines 39 

of brass tubing just large enough to slip over one 
of these screws and cut off three lengths of the 
tube each 1 %e inch long. 

To assemble the case put a screw through each 

4'/*- *t 



musm 




x 



ANGLE 
PLATE 



N%\ 



zzie 



nozzle 




Fig. 21. Construction of the Turbine Wheel-Case 



hole in the plate which carries the nozzle; slip 
one of the tubes over each screw to keep the 
plates apart and insert the shaft of the wheel 
in the center hole of the nozzle plate. Next set 



40 The Boys' Book of Engine-Building 

the case plate with the exhaust hole so that the 
screws will go through the screw holes in it ; put 
on a washer and screw a nut on each screw. 

Cut out four strips of brass for the angle 
plates %e inch wide and 1Y2 inches long, and drill 
a hole in one end of each strip; bend these as 
shown in the cross-section view D in Fig. 21 and 
solder them to the sides of the case plates near 
the corners of the case as shown at A and D. 
These are to be screwed to the bed of the ma- 
chine to hold the case rigidly in place. 

The Bearings for the Shaft. — You can buy the 
bearings for the shaft or you can make them 
yourself. An easy way to do the latter is to cut 
a pattern out of soft pine and cast a couple of 
them in type metal or better, have a molder cast 
them in brass for you. 

Each bearing consists of a standard, that is a 
support, V± inch thick, % inch wide and 2% inches 
long with feet on one end as shown at A and D. 
Smooth up the castings with a file, then drill a 
% 6-inch hole % inch from the plain end and 
thread these holes with a tap to take a /4-inch 
screw. Get two brass machine screws, each % 
inch long, and drill out the ends of the screws 



Two Simple Steam Turbine Engines 41 

%2 inch deep. Also drill a %-inch hole in each 
foot so that the standard can be screwed to the 
bed. 

Mounting the Wheel— Get a piece of boiler 
plate, or any kind of a smooth iron or brass plate, 
about /4 thick, 4 inches wide and 5 inches long 
for the bed. 

Drill four %-inch holes in this plate for the 
bearing standards, two on each side; have each 
pair of holes Wig inch apart and % inch from the 
other as shown in A and B. Tap out these holes 
and screw the standards tight to the bed. 

Set the shaft of the wheel between the bear- 
ing screws and drill a %2-inch hole through the 
bed at the places where the angle plates of the 
wheel case rests on it; thread them with an 8-32 
tap and screw the angle plates down to the bed. 
This completes the steam turbine proper and, 
when done, it will look like Fig. 22. 

The Reduction Gears. — When supplied with 
enough steam, this turbine w y heel will run at 
about 10,000 revolutions per minute, and this, of 
course, is much too speedy for any earthly use. 

To reduce the speed to something like that of 
an ordinary engine a reduction gear is needed, 



42 The Boys 9 Book of Engine-Building 

that is a very small gear, or pinion as it is more 
often called, is made to turn a very much larger 
gear and, of course, this one turns more slowly, 
the rate depending on the relative sizes of the two 




Fig. 22. The Model De Laval Turbine Complete 

gears, or their ratio as it is called. A single re- 
duction gear is shown in Fig. 23. 

Sometimes there is a second small gear fixed 
to the shaft of the large gear ; this small gear is 
made to turn another large gear and this gives 
you a double reduction gear. You can rig up a 
reduction gear by using the wheels and pinions 
taken from an old clock or you can buy them 



^ 



Two Simple Steam Turbine Engines 43 



from dealers in model maker's supplies. For a 
boiler large enough to run this turbine see Chap- 
ter V. 

How the Steam Turbine Works. — You may 
not have noticed it, but the De Laval turbine 




/ 

DRIVING 
GEAR 



\ 

DRIVEN 
GEAR 



Fig. 23. A Pair of Single Reduction Gears 

is both an impulse turbine like Branca's and it 
is also a reaction turbine like Hero's. 

The Action of the Blades. — If you will turn 
back to Fig. 1 1 you will see that the steam from 
the nozzle, when it strikes the blades of the wheel, 
pushes it forward by the impulsive force of the 
energy that is stored up in it. You will also ob- 
serve that, after the steam strikes the curved 



44 The Boys' Book of Engine-Building 

blades, it is thrown out against the air and this 
causes the force of the steam to react on the 
wheel just as it does in Hero's engine. 

How the Nozzle Works. — When steam is al- 
lowed to escape through a simple hole, or orifice, 
a considerable amount of the energy in it is 
wasted in setting up little whirls and other com- 
motions in it and this leaves only a small portion 
of its useful energy to drive the wheel with. 

To prevent these untoward actions as well as 
to make the steam expand 1 in the nozzle, that is 
to change the energy which exists in it as latent 
heat into the energy of motion, a special shaped 
nozzle must be used and this is the purpose of 
the one De Laval designed. 

When the steam from the boiler reaches the 
throat of the nozzle, it falls to about half of its 
initial pressure, that is the pressure delivered by 
the boiler to the nozzle. After passing through 
the throat the steam begins to expand and thus, 
while it decreases in density, in pressure and in 
temperature, the particles of which it is formed 
increase in speed and hence in power. 

1 See Chapter IX, "The Stuff that Steam is Made Of." 



CHAPTER III 

A SIMPLE PISTON STEAM ENGINE 

The Oscillating Cylinder Engine — The Tools You 
Need — The Parts of the Engine: The Cylinder; The 
Piston ; The Crank, Crankshaft and Flywheel ; The En- 
gine Bed — Assembling the Engine : Oiling the Engine ; 
Testing the Engine — How to Make the Boiler — How to 
Run the Engine: About the Lamp — How the Pbwer 
Plant Works — Where to Buy Materials. 

Before you build any of the larger and more 
complex engines which follow, you should by all 
means make the parts of and assemble the simple 
single-acting steam engine described in this 
chapter. 

By building this one you will get a clear idea 
of the way steam acts and how an engine works 
and this will be of great help to you when you 
come to the more powerful slide-valve engines. 

The Oscillating Cylinder Engine. — An oscil- 
lating cylinder engine is one in which the cylinder 
is pivoted in the middle and by rocking up and 
down like a druggist's balance, or oscillating as 

45 



46 The Boys' Book of Engine-Building 

it is called, allows the steam from the boiler to 
pass into and escape from a single port, that is a 
hole, or opening, in one end of the cylinder. 

This kind of an engine is single acting — that is 
the steam is admitted into one end of the cylinder 
and hence there is only one power stroke to each 
revolution of the crankshaft. It can be made 
double acting — that is the steam can be admitted 
into each end of the cylinder alternately and so 
gives two effective power strokes to every revolu- 
tion of the crankshaft. 

The oscillating cylinder engine which I shall 
tell you how to build is a single-acting one and I 
have chosen it because it is the easiest kind to 
make. 

The Tools You Need. — You will need very 
few tools to make this little engine but though a 
couple of them are rather expensive you ought 
to have them anyway as they will prove useful 
for a thousand and one other things. 

Get (1) a small machinist's hammer; (2) a 
hand drill stock and half a dozen twist drills; 
(3) a couple of Hies; (4) a pair of tinner's 
shears; (5) a small bench vise; (6) an alcohol 
blow torch; (7) a jeweller's soldering copper; 



A Simple Piston Steam Engine 47 

(8) ten cents' worth of wire solder, and (9) 
make some soldering fluid by dissolving zinc clip- 
pings in a little muriatic acid. 

The Parts of the Engine. — There are six prin- 
cipal parts to this engine: (1) the cylinder; (2) 
the piston; (3) the piston rod; (4) the crank- 
shaft; (5) the flywheel, and (6) the bed. 

The Cylinder. — To make the cylinder get a 
piece of brass or copper tubing * — it must be 
smooth inside — and have it % inch in diameter, 
inside measurement, 1% inches long and with as 
thick a wall as you can get it. 

File off the cylinder on one side so that it is 
perfectly flat and then drill a hole through the 
middle of the flat side Viq inch in diameter for 
the pivot and another hole of the same size Vs inch 
from the end, all of which is shown at A in 
Fig. 24. 

Take a 6-32 screw, cut off the head and file 
the end of it down until it fits in the middle hole; 
moisten it with a little soldering fluid, turn the 
flame of your blow torch on it for a moment and 
then touch the end of the wire solder to it when 
the latter will run around and join the two pieces 

* Seamless tubing is the best. 



48 The Boys' Book of Engine-Building 

of metal firmly together. Make a spiral spring 
of brass wire just large enough to go over the 
pivot and screw a nut on the latter. 

To make the heads of the cylinder cut out two 
disks of sheet brass, or you can use sheet lead 
which is easier to work, and drill a %-inch hole 




SPIML SPM'to 
SOLDER HEP£ 

—CYLINDER 

Fig. 24 A. The Cylinder and Cylinder Heads 

in the center of one of them. These heads are 
to be soldered to the ends of the cylinder, and 
this can be done better after the piston is 
made. 

The Piston. — Because the piston must slide to 
and fro in the cylinder very smoothly and yet 
close enough to prevent the steam from leaking 



£ 



A Simple Piston Steam Engine 49 

past it, the making of the piston is a most par- 
ticular job. 

Since the inside of the cylinder is % inch in 
diameter, the piston must be nearly the same size. 
Take a piece of brass about %2 inch thick and 
scribe, that is scratch a circle on it with a pair 
of compasses % inch in diameter; drill a %-inch 
hole in the center and file down the piece of brass 

,wo™a/ ^,v SOLDER HBZ£ 

PISTON POD 
jfiHOLE / 



^?a 



s/» 




PISTON 

Fig. 24 B. The Piston and Piston Rod 

until it is a perfect circle and fits the bore of the 
cylinder accurately. 

You can make the piston rod of a straight piece 
of iron wire Vs inch thick and 2% inches long ; file 
off the sides of one end a little and then drill a 
/46-inch hole through it %6 inch from the end as 
shown at B in Fig. 24. This done, fit the other 
end of the piston rod into the piston and be sure 
to get it in straight, and then solder them to- 
gether. 



50 The Boys' Book of Engine-Building 

Having the cylinder and the piston, the next 
thing to do is to slip the cylinder head with the 
hole in it over the piston and put the latter in 
the cylinder with the cylinder head on the end 
of the cylinder opposite the port. Now solder 



CRANKSHAFT 




OLDER HERE 

CRANK 
SOLDER 

CRANK PIN 

Fig. 25 A. The Crank and Crankshaft 

the head to the cylinder using your soldering cop- 
per to do the job. 

Be careful that the head is on so that the pis- 
ton will work forth and back without binding. 
When you have done this, go ahead and solder 
on the other head to the cylinder and the hardest 
part of your engine is made. 

The Crankshaft, Flywheel and Pulley. — A 



A Simple Piston Steam Engine 51 

straight piece of wire %2, or Vs inch thick and 3 
inches long will serve for the crankshaft, that 
is that part of the engine which revolves, to 
which the piston rod is connected and on which 
the flywheel and pulley are fixed. 

For the crank, see A, Fig. 25, cut out a piece 




Fig. 25 B. A Spoked Fly- Wheel 

of brass Yi§ inch thick and % inch long, and make 
one end % inch wide and the other end % inch 
wide; drill a Vi 6-inch hole in the small end and a 
%-inch hole in the large end ; fit in and solder one 
end of the crankshaft to the crank and solder a 
/46-inch wire, % inch long, into the other end for 
the crank pin. 

Almost any kind of a wheel will do for the fly- 



52 The Boys' Book of Engine-Building 

wheel, see B, but it should be pretty large, say 
3 inches in diameter, and it should be rather 
heavy, say about 2 ounces, and the larger it 
is for its weight the smoother the engine will 
run. 

You can cast a flywheel with a little pulley on 
it by sawing out a wooden pattern first, making 
a mould of plaster parts and pouring in some 
melted type metal. 1 An easier way is to buy one 
already cast. 

The Engine Bed. — This is a block of wood 1 
inch thick, 2Y2 inches wide and 5 inches long on 
which to mount the engine; sandpaper it smooth 
and give it a coat of red paint. 

Cut out a frame of a piece of thick sheet brass, 
or heavy tin will do, 4 inches square to the shape 
shown in Fig. 26. Drill a %2-inch hole in the 
center of the circles marked inlet port and ex- 
haust port and in each of those marked bearing; 
also drill a %-inch hole in the circle marked cyl- 
inder pivot and in the screw hole circles. 

Now bend up the sides of the tin or brass on 
the dotted lines to form the frame and solder a 
piece of brass pipe Vs inch in diameter and 6 

1 You can use lead, but it shrinks on cooling. 



A Simple Piston Steam Engine 53 

inches long over the inlet port on the inside of 
the valve plate. 

Assembling the Engine. — You have now 
reached the last and most interesting stage of 




Fig. 26. The Engine Frame 

your work, the assembling of the parts. Begin 
by screwing the frame to the bed of wood and 
have the valve plate and bearing on the side with 
it flush, that is even, with one of the long edges 
of the bed. 



54 The Boys' Book of Engine-Building 

Next slip the crankshaft through the bearings 
of the frame and then fit the flywheel and pulley- 
to the other end and, if these are made of metal, 
solder them on to the end of the shaft. Slip the 
crank pin through the hole in the end of the pis- 
ton rod; put the cylinder pivot through the pivot 




TOBOILER 



Fig. 27. The Oscillating Cylinder Engine Complete 

hole in the frame, set the spiral spring over the 
pivot and screw on the nut. This arrangement 
permits the cylinder to oscillate freely and at the 
same time holds it close to the valve plate. The 
engine complete and ready to run is shown in 
Fig. 27. 

Oiling the Engine. — To keep the steam from 
leaking between the port of the cylinder and the 



A Simple Piston Steam Engine 55 

inlet port of the valve plate, lubricate it, that is 
oil it, with a drop of sewing machine oil and also 
put a couple of drops of oil into the cylinder as 
this will make it run with less friction and keeps 
the steam from getting past it ; finally, put a wee 
drop of oil on each of the bearings and your en- 
gine is ready to run. 

Testing the Engine. — Having put your engine 
together, the next thing to do is to try it out to 
see if it is in working order. All you need to 
do to find out if it will run is to give the flywheel 
a start and blow through the inlet pipe. If you 
have made it right, it will run as long as you 
blow. When it runs to your satisfaction, your 
next need is a boiler. 

How to Make the Boiler. — To make a boiler 
that will raise enough steam to operate this little 
engine is a simple matter. 

Make a can 2% inches in diameter and 6 inches 
long of heavy sheet tin. To do this cut out a 
piece of tin 6 inches wide and 7 inches long; 
bend it on a broomstick until it is a cylinder and 
solder the edges together thus, making a lap 
seam. 

Cut out two disks of tin 2/4 inches in diameter 



56 The Boys' Book of Engine-Building 

and with four ears on each one as shown at A in 
Fig. 28. Bend the ears over and solder the disks 
to the ends of the boiler and do it well. Now 
drill a %-inch hole through the seam 2V2 inches 
from one end and a %-inch hole also through the 
seam 1% inches from one end. 



STEAM PIPS 
-TO ENGINE 



TONGUE 



FILLER 




TOPSEAM 




Fig. 28. Construction of the Boiler 

Make a box of heavy tin, or, better, of sheet 
Russian iron, for the boiler to rest on, 3 inches 
high, 3 inches wide and 5 inches long. This can 
be made of a single piece of sheet metal by 
marking out a template, that is a pattern as 
shown at C in Fig. 28. Draw the pattern out 
full size on a sheet of paper and paste it on the 
tin or sheet iron. Drill a dozen %-inch holes 



A Simple Piston Steam TLngine 57 



near the top on the sides and a dozen or more 
holes of the same size near the bottom in the 
middle so that the flame can get plenty of air and 
the heat will be kept in at the same time. 

Bend the iron or tin into the form of a box 
and then bend out the edges at the bottom and 
bend in the edges at the top. Now make a wood 




OQgpO 

filR HOLES 
SCREW HOLES 




RlVETHOLE 



&^"6'^^ < v'/K~~6"" 



00000 

AIRHOLES : 

6" A"6 i 



-3& 



2 

17k' 




Fig. 28 C. The Fire-Box 

base 1 inch thick, 5 inches wide and 7% inches 
long. Screw the flanges of the box on the base 
leaving a margin of V2 inch all round. Set the 
boiler in the concave ends of the box, as shown 
in Fig. 29, and bring the steam pipe up from the 
engine and bend it so that it will fit close to the 
small hole in the top of the boiler and solder it 
fast. 

Half-fill the boiler, through the large filler hole, 
with clean water and put a cork in the hole; the 



58 The Boys' Book of Engine-Building 

cork will not only keep the steam in, but it will 
act as a safety valve, for it will blow out before 
the boiler blows up should the steam pressure get 
too high. 

There is only one more part to make before 
your miniature power plant is complete and this 



TOENG/NE 




Fig. 29. The Boiler Mounted on the Fire-Box 



is the furnace to heat the water in the boiler. 
Get, if you can, or make, if you have to, a tin 
salve box about % inch high and 2 inches in diam- 
eter. Drill, or punch, a %-inch hole through the 
center of the lid and solder a tin tube % inch in 
diameter and % inch high in it for the burner; 



A Simple Piston Steam ILngine 59 

drill a /46-inch hole in the outer edge of the lid for 
a vent ; make or buy a braided cork wick to fit the 
burner, about 1% inches long, and put it through 
the tube. 

How to Run the Engine — Filling the Boiler. — 
By filling the boiler with boiling hot water it will 
not only make steam quicker but it will save alco- 
hol. Be sure the water is clean or else the steam 
port of the engine may get choked up and then 
the engine will run slowly or stop altogether. 
And be careful the boiler does not run dry. 

About the Lamp. — Have the wick just a trifle 
above the tube and half-fill the lamp with wood 
alcohol. Wipe off any alcohol that may be 
spilled on it in filling and then light the wick. 

If the water is boiling hot when you put it in 
the boiler and the flame of the lamp is burning 
blue, it will take about five minutes to get up 
steam. At the end of this time turn the fly- 
wheel around several times to clear out the steam 
which has condensed in the cylinder and, if the 
steam is under sufficient pressure, your engine 
will run like sixty. 

How the Power Plant Works. — First the heat 
of the lamp changes the water in the boiler into 



60 The Boys' Book of Engine-Building 

steam and, when the latter is hot enough, it is un- 
der pressure. 

Now when the piston is at the back end of the 
cylinder, the port is then just even with the open- 
ing of the pipe in the valve plate; the steam un- 
der pressure rushes into the cylinder and forces 
the piston forward; as the crankshaft turns 
round the rear end of the cylinder is raised until 
the port is even with the exhaust hole in the valve 
plate and this permits the used steam to escape 
into the air. 

By this time the crankshaft will have made 
one complete revolution and the cycle of opera- 
tion will begin all over again. It is indeed a 
pretty mechanical movement. 

Where to Buy Materials. — You can buy a cyl- 
inder and piston for thirty cents and a flywheel 
for the same price ready-made of the Weeden 
Manufacturing Company, New Bedford. Mass., 
or you can buy an engine and a boiler complete, 
very like the one I have described, of the above 
firm for $1.50. 



CHAPTER IV 

A y 24 -H. P. HORIZONTAL STEAM ENGINE 

The Tools You Need: The Drawing Tools; The 
Wood Working Tools; The Metal Working Tools — 
Drawing the Plans of the Engine — The Parts of the 
Engine — How to Make the Patterns: The Cylinder: 
The Cylinder Heads, The Piston; The Steam Chest, The 
Slide Valve; The Cross Head Guide; The Crank; The 
Eccentric; The Pillow Blocks; The Bed Plate — Mould- 
ing the Parts in Metal — Finishing the Castings: The 
Cylinder ; The Steam Chest ; The Piston and Piston Rod ; 
The Slide Valve and Valve Stem; The Cross Head 
Guide: The Cross Head Guide Block, The Rocker Arm, 
The Valve Stem Bearing; The Connecting Rod; The 
Crank and Crank Shaft; The Eccentric Rod; The Ec- 
centric; The Flywheel; The Pillow Blocks — Mounting 
the Engine on the Bed Plate — Setting the Engine on Its 
Bed — The Auxiliary Parts — How the Engine Works — 
Calculating the Horse Power of a Steam Engine. 

There are three ways to go about making an 
engine of this size and kind and you can choose 
the one that suits your pocket and your purpose 
the best. 

The easiest way is to buy a complete set of 

castings (See Appendix D), have such machine 

61 



62 The Boys' Book of Engine-Building 

work done on them as may be needed and then 
assemble the parts. 

The second way — and this is my idea of build- 
ing the engine — is to make patterns of all the 
parts yourself, have them cast in iron or brass 
at a foundry, get a machinist to bore the cyl- 
inder and the ports in it, and bore and turn the 
flywheel, when you can do the rest of the work 
and assemble it without trouble. 

A cheaper but less satisfactory way is to make 
the patterns as before and cast them yourself 
in type-metal. Castings of this metal are very 
sharp and yet quite soft, hence they can be easily 
worked. When it is done in this way, the en- 
gine will make a good working model, but you 
will have to handle it very gingerly to keep it 
from getting marred. 

The Tools You Need. — These consist of ( i ) a 
few drawing tools; (2) some woodworking tools, 
and (3) a fair assortment of metal working 
tools. 

The Drawing Tools. — You can get all the 
drawing tools you need for a dollar or more. 
The necessary ones are (a) an 11x15% inch 
drawing board; (b) a good accurate rule — an 



A Yzi-H. P. Horizontal Steam Engine 63 

architect's triangular boxwood scale is the best; 

(c) a 30 ° triangle; (d) a T square as long as 
the board; (e) a pair of 4-inch dividers; (f) a 
pair of 4-inch compasses; (g) an eraser, and (h) 
a good, medium-soft lead pencil. 

The Wood Working Tools. — These can be lim- 
ited to (a) a small block plane; (b) a scroll saw 
frame and saw blades; (c) a small back saw; 

(d) a miter box; (e) a brace and %-, % and %- 
inch bits; (f ) a try square and (g) a good pocket- 
knife. 

The Metal Working Tools. — The following 
list of tools includes about everything you need 
and while you might get along with a few less 
you could, of course, use several more. 

Get (a) a jeweller's saw frame and saws; (b) 
a jeweller's hammer; (c) a small machinist's 
hammer; (d) a center punch; (e) a pair of 
spring dividers; (f) a pair of tinner's shears; 
(g) a hand drill stock and an assortment of twist 
drills; (h) an alcohol lamp; (i) a jeweller's sol- 
dering copper; (j) a pair of flat-nose side cutting 
pliers; (k) a couple of screw drivers; (1) some 
files; (m) a set of taps and dies; (n) a carborun- 



64 The Boys' Book of Engine-Building 

dum oil stone; (o) an oil can filled with sewing 
machine oil, and (p) a vise. 

Drawing the Plans for the Engine. — The first 
thing to do is to draw all the separate parts of the 
engine shown in Fig. 31 on a sheet of paper full 
size and mark on the dimensions. You will then 




Fig. 30. T- Square and 30 Degree Triangle on Drawing Board 

have a set of drawings that you can work from 
much better than those shown in the book. 

I have made the drawings of the parts in what 
is called isometric perspective so that you can 
clearly see the design, construction and dimen- 
sions at a glance. To make the drawings fasten 
a sheet of paper on the board with thumb-tacks ; 
lay your T square on the board with the 30 de- 
gree triangle on the upper edge of it as shown 



A V24-H. P. Horizontal Steam Engine 65 

in Fig. 30; you can then draw 30 degree lines 
which are used for isometric pictures. 

The Parts of the Engine. — This little horizon- 
tal engine is formed of the following parts : ( 1 ) 
the cylinder; (2) the steam chest; (3) the piston 
and piston rod; (4) the slide valve and slide valve 
stem; (5) the cross head guide; (6) the cross 
head guide block; (7) the eccentric rod rocker 
arm; (8) the connecting rod; (9) the eccentric 
rod; (10) the crankshaft and crank; (11) the 
eccentric; (12) the flywheel; (13) the pillow 
blocks; (14) the bed plate, and (15) the bed, all 
of which will be described in detail as we go 
along. 

How to Make the Patterns. — All the patterns 
are made of wood which must be well seasoned ; 
soft pine without knots and having a straight 
grain is the easiest wood to work. You can 
build up each part of as many pieces of wood as 
you want, but be sure that they fit and glue them 
well together. 

Each part must be built up exactly as you want 
the casting to appear when finished, only a trifle 
larger to allow for shrinkage and machining; 
and to make the pattern draw from the mould 



66 The Boys' Book of Engine-Building 

smoothly sandpaper it with fine sandpaper until 
it seems to be one solid piece ; but in sandpapering 
it be careful not to round off any edges that 
should be sharp. After sandpapering give the 
pattern a couple of coats of shellac varnish and 
it is then ready for the moulder. 

The Cylinder. — Take a piece of clear pine i% 
inches square and 2 inches long and bore a hole 
through the middle of it % inch in diameter; 
plane it down until it is 1% inches across on top, 
% inch wide and flat on the sides and 1% inches 
in diameter on its rounded side as shown at A 
in Fig. 31. 

This will make the wall of the cylinder, that is 
its thickness, %6 inch thick. You won't need to 
drill the port holes in the pattern as it can be 
done to better advantage in the casting when it 
is made. 

Saw out two rings of wood Vs inch thick and 
make the inside diameter of each one % inch 
and the outside diameter 1% inches; glue a ring 
to each end of the cylinder for the flanges and 
screw them up in a clamp or a vise until the 
glue has set. 

Next saw out two feet, as shown at B, % inch 



M>A 




.f 


f\ 


^s. 







*<c 


\^y 




i-l 


yy^r^\ 


v ^> 




67 



68 The Boys' Book of Engine-Building 



wide, % inch high and i% inch long; make the 
foot proper Vs inch thick, round the top of the pat- 
tern so that it will fit the cylinder and glue a foot 
to each side of the latter as shown in Fig. 32. 
When the glue has set, sandpaper and shellac the 
pattern and it is ready for the moulder. 



SLIDE 
V/ILVE 



STEAM 
CHEST 



CYLIND { 
HE/fD 

CYLINDER. 
PISTON 




INLET 



FOOT 



FOOT 

Fig. 32. An End View of the Engine 

The Cylinder Heads. — It is much easier to 
make patterns for the cylinder heads than it is 
to cut them out of sheet metal. The back cyl- 
inder head, see C, is simply a disk Vs inch thick 
and 1% inches in diameter. 

The front cylinder head is the same size but 
it has a ring on it % 6 inch long with a bore V2 
inch in diameter and an outside diameter of % 
inch as shown at D. This ring forms the stuff- 
ing box and allows the piston to be packed, which 



A V24~H. P. Horizontal Steam Engine 69 

keeps the steam from escaping around it. The 
k small ring that holds the packing in can be cut 
out of a piece of sheet brass. 

The Piston. — Saw out a disk of wood /4 inch 
thick and iVie inches in diameter for a pattern 
for the piston. 

The Steam Chest. — This is simply a box open 
at the bottom. It is Vs inch thick, % inch high, 
13 Ae inch wide and 1 V2 inches long, outside meas- 
urement, as shown at E. 

Glue a strip Vs inch thick, Vie inch wide and 1 V2 
inches long on each side of the box along the 
bottom; this will make it just the width of the 
top of the cylinder but V2 an inch shorter in length. 
Now glue a disk % inch thick and V2 inch in 
diameter in the center and on top of the steam 
chest and then glue a ring 34 inch long with a Vie 
inch bore and an outside diameter of Vie inch on 
one end of the chest. This is for the stuffing 
box. 

The Slide Valve. — Saw out a block Vie inch 
thick, V2 inch wide and % inch long; cut out one 
side with a chisel, or your knife; so that it will 
be Vie inch deep, 34 inch wide and Vie inch long. 
Cut out a block % inch square and glue it to the 



JO The Boys' Book of Engine-Building 

center of the top of the slide valve as shown at F ; 
to this is fastened the slide valve rod. 

The Cross-Head Guide. — You only need one 
pattern for the supports, see G, and have two 
castings made of it. Saw out a strip of wood 
%e inch thick, % inch wide and 2 inches long 
and glue a block Vs inch thick, % inch wide and 
% inch long to one edge at each end for feet so 
that the castings can be screwed down to the 
bed-plate. 

The Crank. — From a piece of wood V2 inch 
thick and 1 inch long cut out a crank as shown 
at H. Make one end V2 inch wide, the other end 
V± inch wide and round off both ends. The fin- 
ished metal crank is used to connect the con- 
necting rod to the crankshaft. 

The Eccentric. — For this pattern cut out a disk 
% inch thick and % inch in diameter as shown 
at I. 

The Flywheel. — You can buy an iron flywheel 
in the rough with a %-inch face and 5 inches in 
diameter for 25 cents. 

If you want to make a pattern and have it 
cast, so much the better, but you must expect to 



A V24-H. P. Horizontal Steam Engine Ji 

spend a lot of time on it. Make it with six 
spokes and saw it out with your scroll saw. 

The Pillow Blocks. — These are to support the 
crankshaft and to provide the bearings for it. 
Each block has a cover as shown at J. 

To make a pattern saw out a block of wood V2 
inch wide, 1 inch high and 1% inches long to the 




Fig. 33 A. Top View of the Engine with Cylinder and Steam 
Chest in Cross Section 



shape shown at J. Have the base % inch thick 
and the bearing %6 inch thick, V2 inch wide and % 
inch long and make the cover the same size and 
cast them separately. 

The Bed Plate. — This is the plate to which the 
cylinder and other parts of the engine are bolted 
and it should be cast in iron. 

Make a frame of %-inch stuff, 1 inch deep, 3 
inches wide and 9% inches long and put a top on 
it Vs inch thick. Cut out six blocks /4 inch thick 



72 The Boys' Book of Engine-Building 

and % inch square and glue one to each corner 
of the bed plate at the ends and one to each side 
in the middle. These are to permit the bed plate 
to be bolted to the bed. 

Moulding the Parts in Metal. — When all of 
the patterns are finished, take them to a foiindry 
and have them cast in iron, or, better, in brass. 

As the amount of metal in the castings is small 
the cost will be about the same for either. On 
the whole brass castings are the best because they 
are finer grained, easier to work and make a 
handsomer engine. 

Finishing the Castings. — When you get the 
castings from the foundry they will be a little 
rough all over and the working parts and those 
that fit together must be smoothed and trued up 
either with a file or in a lathe. If you own a 
lathe fitted with a slide rest, you can do all the 
work yourself, but if you haven't one, then get 
some genial machinist to help you out. 

The Cylinder. — This must be bored out with a 
I -inch drill to make it smooth and of the right 
size. If you have a machinist do this for you, 
you might as well let him drill the ports and 
screw holes through the flanges and cylinder 



A %4-iJ. P. Horizontal Steam Engine 73 

heads as well as the steam chest and the steam 
chest plate. 

If you drill the ports yourself, use a %6-inch 
drill and start it % inch from the center of the 
cylinder on the plate the steam chest sets on; 
drill the hole at an angle of nearly 40 de- 
grees, until it goes through and meets the bore 
at a point just inside the flange as shown in the 
top view T , Fig. 33. Then drill another hole of 
the same size for the other intake port and at 
the same angle on the opposite side of the 
plate. 

For the exhaust port drill a %-inch hole 
straight down through the center of the steam 
chest plate to a depth of /4 inch; now drill the 
same sized hole on the other side of the cylinder 
from that on which the foot is cast and through 
the cylinder until it meets the first hole. This 
makes a passage clear through from the steam 
chest to the open air for the exhaust steam to 
escape. 

Drill four holes in the steam chest plate at the 
points shown in the side view in Fig. 34 and 
thread them with an 8-32 tap so that the steam 
chest can be screwed to the cylinder. Drill a 




74 



A V2±-H. P. Horizontal Steam Engine 75 

% 6-inch hole through the center of the cylinder 
head with the stuffing box on it. 

Next make a ring of /46-inch thick sheet brass 
% inch in diameter and with a % 6-inch hole in 
its center. Drill two %2-inch holes through the 
ring on opposite side of it, drill two Vi 6-inch holes 
in the face of the stuffing box and thread these 
holes so that the ring can be screwed to it, all 
of which is shown at D in Fig. 31. 

Drill four %2-inch holes at equal distances 
apart through both of the cylinder heads and into 
the ends of the cylinder; then thread the latter 
holes so that the heads can be screwed to them. 

The Steam Chest. — Drill a % 6-inch hole 
through the top of the steam chest for the inlet 
pipe and thread it to take a %-inch pipe. Drill a 
%-inch hole through the end with the stuffing 
box on it for the slide valve stem and drill two 
/46-inch holes in the stuffing box and thread them. 

Make a ring %6 inch in diameter, cut a hole 
in it %2 inch in diameter and drill two holes near 
the outer edge so that it can be screwed to the 
stuffing box. Drill out two holes on one side of 
the steam chest, and thread them so that the 
chest can be screwed down to the bed plate. 



j6 The Boys' Book of Engine-Building 

File the inside edges of the chest true and 
smooth and finish up the outside of it with a file. 
Two views of the steam chest are shown at E in 

Fig. 3i. 

The Piston and Piston Rod. — The piston cast- 
ing can be filed down or it can be put in a lathe 
and then turned down so that it fits the cylinder 
closely and yet will slip through it without bind- 
ing ; a half round groove should be filed or turned 
in its face. Drill a %-inch hole through the cen- 
ter of the piston for the piston rod. 

A good straight piece of soft steel rod, % inch 
in diameter and 3% inches long, will make a good 
piston rod; thread both ends of it, screw a nut 
on one end, slip the piston on and screw another 
nut on tight. Wrap some soft cotton cord on 
the piston until the groove is full and soak it in 
sewing machine oil; work it back and forth in 
the cylinder until it slides easily. 

Now slip the piston rod through the cylinder 
head with the stuffing box on it and screw the 
latter to the flange of the cylinder ; likewise screw 
the plain cylinder head on to the other end of 
the cylinder. 

Soak some cotton cord in oil and pack it around 



A Yii-H. P. Horizontal Steam Engine yj 

the piston rod in the stuffing box until it is full, 
and then screw the ring to the latter to hold it 
in. 

The Slide Valve and Valve Stem. — File the 
sides of the slide valve until it fits the inside of 
the steam chest to a nicety and file the bottom of 
it until it slides on the cylinder plate accurately. 

Drill a /46-inch hole in the boss of the valve, 
%e inch from its lower edge, and thread it to 
take the valve stem. Make the stem of a piece 
of soft steel rod %2 inch in diameter and 3% 
inches long and thread both ends of it. Put the 
slide valve in the steam chest, slip the stem 
through the hole in the chest and screw it into 
the slide valve; now pack the stuffing box with 
oiled cord as described above and screw on the 
ring. 

Finally, screw the steam chest to the slide valve 
plate of the cylinder and the hardest part of your 
engine is done. 

The Cross-Head Guide.— File the top and bot- 
tom faces of the guide supports true and smooth 
and drill two /46-inch holes in the top face of 
each one V* inch from the ends and thread them. 
Also drill a %-inch hole in each foot and a %-inch 



yS The Boys' Book of Engine-Building 

hole in the middle of one of the supports for the 
rocker arm. 

Cut off four strips of brass Vs inch thick, % 
inch wide and 2 inches long for the guides. Drill 
two %2-inch holes through each strip %2 inch 
from one edge so that when it is screwed to the 
support it will lap over Vie inch. This done, saw 
off four pieces of % 2 -inch brass tubing, %6 inch 
long, to keep the guides apart. 

Now put a 4-36 screw through each hole in 
one of the guide strips, slip a tube over each 
screw, slip another guide strip over the screws 
and screw them to the support as shown at G 
in Fig. 31. Do the same thing with the other 
guide strips and support and your cross-head 
guide is done. 

The Cross-Head Guide Block. — This is a block 
of metal to which the piston rod is secured and 
which slides in the cross-head guide. To make 
it take a bar of brass % inch square and file out 
the corners on opposite sides to a depth of % inch 
and on the other sides to a depth of Vi6 inch as 
shown at K in Fig. 31. 

It must slide to and fro the length of the guide 
easily and yet without the slightest play. A 



A V24-H. P. Horizontal Steam Engine 79 

cross section view of the cross-head guide and 
the guide block is shown in Fig. 35. Drill a 
%-inch hole through it, thread it with an 8-32 
tap and screw it to the free end of the piston rod. 
The Rocker Arm. — This is to connect the slide 
valve stem with the eccentric rod. Cut off a 
piece of brass %2 inch thick, % 2 inch wide and % 



ROCHE R jQRM 

\ P/AL 




GU/DES 



SUPPORT 



ROCKER* 

Fig. 35« The Rocker Arm and Cross-head Guide 



inch long; file it down until it is % inch wide at 
one end ; file the ends round and drill two %-inch 
holes, %e inch apart, as shown in Figs. G 31, 34 
and 35. 

Make a brass washer Vs inch thick and % inch 
in diameter with a %-inch hole in it; slip a %- 
inch long 8-32 screw through the hole in the 
large end of the rocker arm, put on the washer, 



80 The Boys' Book of Engine-Building 

set the screw through the hole in the guide sup- 
port and screw a couple of nuts on it. 

Cut off a piece of steel rod Vs inch in diameter 
and % inch long for the rocker arm pin and 
thread both ends of it; screw a nut on one end, 
%e inch down, put this end through the end in 
the upper end of the rocker arm and screw a nut 
on it as shown at G in Fig. 31 and in Fig. 35. 

The Valve Stem and Bearing. — The valve 
stem, see Figs. 32 and 34, is a steel rod %2 inch in 
diameter and 3% inches long threaded on both 
ends. Make a bearing to connect the valve stem 
to the rocker arm by filing down a piece of brass 
rod, /4 inch in diameter and %6 inch long, on 
both sides until it is Ys inch thick for %2 of an 
inch of its length. 

Drill a %2-inch hole in the large end and thread 
it to fit the end of the valve stem ; drill a %-inch 
hole through the flat end and file it out with a 
half-round jeweller's file so that when it is on the 
pin of the rocker arm it can move to and fro in 
a straight line without binding and at the same 
time without any lost motion. It is shown at L 
in Fig. 31. 

The Connecting Rod. — This can be made of a 



A V24-H. P. Horizontal Steam Engine 81 

straight strip of brass Vs inch thick, %e inch 
wide and 4% inches long. Drill a %2-inch hole 
in one end and a %-inch hole in the other end. 
The centers of the holes should be exactly 4% 6 
inches apart. The connecting rod is shown 
coupled to the cross-head guide block and to the 
crank in the side view Fig. 36. 

The Connecting Rod Bearing. — The connect- 
ing rod is coupled to the cross-head guide block 
by a bearing made of a piece of brass rod Vs2 
inch square and V2 inch long. File dow r n one 
end until it is Vs inch in diameter for %e inch of 
its length and thread it. 

Drill a %2-inch hole through the other end and 
saw and file a slot %2 inch wide and % inch deep 
as shown at M in Fig. 31 so that the thin end of 
the connecting rod will fit in it. Put a pin 
through the bearing and the connecting rod and, 
while it must fit the bearing tight, the connecting 
rod must swing easily on it. 

The Crank and Crankshaft. — Drill a % 2 -inch 
hole through the large end of the crank casting 
and a %-inch hole through the small end and 
have these holes exactly % inch apart between 
their centers as shown at M in Fig. 31. 



I^& 



*% 

*«%>& 




ctS 
u 

u 

o 
be 

a 
d> 

o 
U 

> 

O 



• ¥■* 



CO 

E 



82 



A V24-H. P. Horizontal Steam Engine 83 

Drill a /46-inch hole through the large end of 
the crank at right angles to and through it, until 
it meets the hole drilled for the crankshaft; 
thread the hole and put in a screw pointed at the 
end for the set screw. Now put a %-inch thick 
bolt through the connecting rod and the crank 
and screw on a nut. 

For the crankshaft get a piece of soft steel 
rod % 2 inch in diameter and 2V2 inches long. 
Start a drill hole Vs inch from one end, another 
%e inch from the other end and a third hole i%6 
inch from the first end of the crankshaft but on 
the other side of it — that is the first and second 
holes will be 10 degrees apart as shown at N. 
Drill these holes about %2 of an inch deep to 
form cavities for the pointed set screws. 

Fit the crank on the end of the crankshaft that 
you drilled first and screw in the screw until the 
pointed end of the latter sets in the cavity in the 
shaft and this will hold them securely together. 

The Eccentric. — Turn on a lathe, or file out by 
hand, a groove Vis inch deep and /4 inch wide in 
the rim of the eccentric as shown at I; drill a 
% 6-inch hole exactly r A inch from the center of 
the disk and drill a /46-inch hole through the 



84 The Boys' Book of Engine-Building 

groove at the point where it is nearest the shaft 
hole until they meet. 

Countersink the small hole, thread it and put 
in a flat head machine screw with a pointed end. 
Slip the eccentric over the shaft so that the 
pointed screw is directly over the cavity nearest 
the middle of the shaft and force the screw in 
until the eccentric is firmly fixed to the shaft and 
the head of the screw is flush with the face of 
the groove. 

To make the strap for the eccentric take a strip 
of brass Vi6 inch thick, % inch wide and 3% 
inches long; drill a %2-inch hole in each end, then 
bend the strip of brass on an iron rod about V2 
inch in diameter, hammering it into a ring with 
a wooden mallet, and bend out the ends as shown 
at I. Now slip the strap into the grooved ec- 
centric and you are ready to make 

The Eccentric Rod. — This is simply a strip of 
brass %2 inch thick, }4 inch wide and 3% inches 
long. Drill a %-inch hole in one end to fit the 
rocker arm pin and saw a slot %2 inch wide and 
/4 inch deep in the other end. 

Cut out a piece of brass %i inch thick, Vi inch 
wide and % inch long; drill a %2-inch hole in one 



A V24-H. P. Horizontal Steam Engine 85 

end of this piece and saw a slot %2 inch wide and 
/4 inch deep in the other end. Now slip the 
slotted ends of the two pieces of metal together 
as shown at P and solder them. 

Place the end between the ends of the eccen- 
tric strap, put a screw through the holes of all 
of them and screw on a nut, all of which is 
shown in Fig. 34. The strap must fit into the 
groove of the eccentric to prevent any play but 
it must not bind. Slip the other end of the ec- 
centric rod over the rocker arm pin and screw 
on a nut. 

The Flywheel. — Should you have the flywheel 
cast, or buy it in the rough, you must face it, or 
have it faced, in a lathe — that is the rough sur- 
face must be cut off with a turning tool. 

Then bore a % 6-inch hole through the exact 
center of it so that it is perfectly balanced. Drill 
a %2-inch hole through the hub of the wheel, 
thread it and put in a pointed machine screw. 
Adjust the flywheel on the end of the shaft and 
screw up the set screw. 

An iron flywheel casting can be bought for 
25 cents, as I have said before, and a brass one 
can be had for about 75 cents. It will cost an 



86 The Boys' Book of Engine-Building 

additional 50 or 75 cents to have a hole bored in 
the wheel for the shaft and to face it. 

The Pillow Blocks. — If these are cast in brass, 
they will make very good bearings. Drill a %- 
inch hole in each foot and drill a % 6-inch hole in 
each end of the cover and on through into the 
block to a depth of % inch ; thread the latter holes 
in the block and ream out the holes in the cover 
to a diameter of Vs inch for the screws. 

Now screw the covers to the blocks tight, and 
drill a %6-inch hole through each cover and block 
to form bearings as shown at J. The centers of 
these holes must be precisely % inch from the 
base of the block and they must be drilled true 
for, if the holes are the slightest bit out of line 
the shaft will bind. 

To keep the shaft in place when it is set in 
the pillow blocks get, or make, two brass collars, 
or washers will do, Vs inch thick, % inch in diam- 
eter and with a % 6-inch hole in each one. These 
collars must be put on over the ends of the crank- 
shaft before the crank and the flywheel are fixed 
to it. 

Mounting the Engine on the Bed Plate. — The 



A V24-H. P. Horizontal Steam Engine 87 

top of the iron bed plate should be planed off, but 
if this means an outlay of too much money, then 
file down those parts of it where the cylinder 
and steam chest, the cross-head guide and the pil- 
low blocks are to rest on it with a mill file. 

Now comes a ticklish job — the drilling of the 
bed plate to correspond to the holes in the parts 
above named so that they can be bolted down to 
it. The safest way to do this is to mark out a 
sheet of tin the exact size of the bed plate, set 
the parts on it in the positions shown in the top 
and side views, Figs. 33, 34 and 36, and scribe 
the positions of the holes on it. 

Punch holes through the template, as a tin pat- 
tern is called, with a center punch, lay it on top 
of the bed and make corresponding dents in the 
latter by hitting the center punch with a ham- 
mer. 

Next drill all holes with a %-inch drill and also 
drill a % 6-inch hole through each foot. You can 
now bolt the parts to the bed plate and feel rea- 
sonably sure that each one will be in exactly the 
right place. 

Setting the Engine on Its Bed. — To raise the 



88 The Boys' Book of Engine-Building 

engine from the surface it is to set on high enough 
for the flywheel to clear it the bed plate must 
be set on a bed. 

This can be made of a block of wood i inch 
thick, 4% inches wide and about 12 inches long. 
One corner must be cut out to allow a free space 
for the flywheel to run in. Finally, screw the 




Fig. 37. The Engine Complete 

bed plate to the bed and your engine is finished 
and all ready to run. It is shown as it looks 
when done in Fig. 37. 

The Auxiliary Parts. — The steam pipe and 
fittings and the governor for this engine will be 
described in Chapter VII, "Auxiliary Parts for 
the Steam Engine." Specifications for the boiler 
to run it will be found in Chapter V, "On Making 
Small Boilers" while the safety valve, steam 



A Y24-H. P. Horizontal Steam Engine 89 

gauge, gauge cocks, whistle, etc., will be de- 
scribed and pictured in Chapter VII. 

How the Engine Works.— To understand 
how a slide valve engine works look at the cross- 
section view shown in Fig. 33 and imagine that 
the steam chest is connected to a boiler of the 
right size to run it. 

Now as far as the mechanical operation of the 
engine is concerned it works like this : The steam 
from the boiler is forced under pressure into the 
steam chest and then on through one of the inlet 
ports into the cylinder. 

Since the piston is at this end, the steam press- 
ing against it pushes it to the opposite end of the 
cylinder; as the piston moves back it does two 
things, namely : ( 1 ) it pushes the used steam up 
through the other port and into the slide valve 
which at this instant also opens into the exhaust 
port and, hence, the steam passes out and into the 
open air, (2) it pulls the crank half way around 
and this, of course, turns the crankshaft with it. 

The eccentric, which is fixed to the crankshaft, 
of course, turns half way around too, but it is 
so placed on the shaft — 180 degrees from the 
crank — that its operation moves the slide valve, 



90 The Boys' Book of Engine-Building 

to which it is connected by the eccentric rod and 
slide valve stem, in the opposite direction to that 
of the moving piston. 

The instant the slide valve slides across the 
slide valve plate it connects the first inlet port 
with the exhaust port; at the same time it opens 
the other intake port from the steam chest into 
the cylinder and the piston is forced the other 
way. In this fashion the steam acts first on one 
side of the piston and then on the other, driv- 
ing it forth and back. 

The purpose of the flywheel is to carry the 
crank around past the dead centers; that is the 
points where the piston reverses its direction and 
consequently where the steam ceases to act on it. 
For the same reason the flywheel, due to its in- 
ertia, as it is called, steadies the motion of the 
engine. How the steam in the cylinder acts on 
the piston and forces it from one end of the cyl- 
inder to the other will be described in Chapter 
VIII, on "How Steam Works!' 



CHAPTER V 

MAKING SMALL BOILERS 

A y 12 Horse Power Vertical Tube Boiler: A Simple 
Iron Boiler: The Shell, The Smoke Box, The Firebox: 
The Grate; Gas and Liquid Fuel Burners; A Good 
Copper Boiler: The Shell, The Smokebox, The Firebox, 
Fittings for the Boiler — How to Test the Boiler — A Safe 
Way to Operate a Small Boiler. 

In this chapter I shall tell you how to make two 
small boilers. The first is a vertical boiler large 
enough to run the steam turbine, described in 
Chapter II, or the horizontal engine, described 
in the last chapter, at full speed. 

A boiler should be at least twice the horse- 
power of the engine it is to run. Now you can 
make a boiler according to the plans and speci- 
fications I have given or you can figure one out 
according to the rules laid down at the end of 
this chapter and design and construct it to suit 
yourself. 

A %2-Horse Power Vertical Tube Boiler. — 

This boiler is of the single tube type, that is it 

91 



92 The Boys' Book of Engine-Building 

has a fire-tube, or flue, running up through the 
middle of it so that the fire not only acts on the 
fire-box sheet, as the end of the boiler next to the 
fire is called, but it also heats the tube, and hence 
the water around it, as the burning gases pass 
through it to the smoke stack. 

It takes a steam pressure of about 8 or 10 
pounds to run the %4 h.p. engine, and a boiler 
6 inches in diameter and not less than 8 inches 
high must be used, for, if it is any smaller, it 
will not make steam fast enough. Better make 
it a third or a half larger than this size and be 
sure of a continuous performance. 

There are a couple of simple ways to make a 
small boiler and I will explain and picture both 
of them and you can take your choice. 

A Simple Iron Boiler — The Shell. — Have a 
steamfitter cut a piece of iron pipe for you 6^4 
inches in diameter, outside measurement, and g 
inches long, and thread both ends of it. 

Also have him fit a cap to each end of the pipe 
and bore a i-inch hole through the center of each 
one. Now drill, or have drilled, a %-inch hole 
on each side of and 2 inches from the center hole 
in the top cap as shown in the cross section view 



tV-A 



SAFETY YME\ 



$T£AMP/P£ 
TQSA/G/HE 



I SMOKE &Q%QAP 



FIREBOX 




WATER 
TUBE 



Fig. 38. Cross-section View of the Copper Boiler 



93 



94 The Boys' Book of Engine-Building 

Fig. 38, and the top view, Fig. 39, and thread 
them. 

Cut off two pieces of %e inch pipe 2V2 or 3 
inches long and thread both ends of them. 
Screw a nut on each end of each pipe, smear the 

smoke 

BOX SHEET 
SMELL 




Fig. 39. Top View of the Boiler 



ends with red lead, screw them into the holes in 
the cap and then screw another nut on the end 
of each pipe, as shown in Fig. 38. This done, 
screw both caps on the ends of the large pipe 
good and tight. 



Making Small Boilers 95 

Next get a seamless copper tube 1 1 inch in di- 
ameter and 9% inches long; put it through the 
holes in the caps, or iire-box and smoke-box 
sheets as they are now called, so that it projects 
through each one Vs inch. This done the ends 
of the Hue, as a single fire-tube is usually called, 
must be expanded, that is spread out all around 
to make it fit steamtight as shown in Fig. 38. 

To do this get a piece of iron rod 1 inch in 
diameter and 3 inches long and turn it down in 
a lathe, or file it down until it tapers enough so 
that the small end will easily go into the tube; 
now drive this tool, or swage, as it is called, see 
A, Fig. 40, into and pull it out of an end of the 
tube until the latter is made larger, or expanded, 
when the tube will crowd up close to the sheet, 
or cap, and form a steamtight joint. It is a good 
plan to run some solder around the joint to fur- 
ther insure its being tight. 

Make a peening tool of a bar of iron say X A 
inch square and 3 inches long — the exact size 
doesn't matter — and file a notch in one end as 

1 Can be bought of V. T. Hungerford Brass and Copper Co., 
80 Lafayette St., New York, or of Patterson Brothers, 27 Park 
Row, New York City. 



96 The Boys 9 Book of Engine-Building 

shown at B. Set this tool with the notch on 
the rim of the tube and pointed outward; then 
with the aid of your hammer gently turn the rim 
down all around until it laps over the sheet and 
fits tight up to it. Do the same thing with the 
other end of the tube and the boiler shell is done. 




1 



^ 

i 



rV 



3 



A 



V /. 



^'Af 



00 



Fig. 40. Swage and Peening Tools 



Drill %-inch holes in the boiler shell at the 
places shown in the cross-section view, Fig. 38, 
and thread them to fit %-inch iron piping. Then 
screw a piece of %-inch pipe, 1 inch long, 
threaded at both ends and smeared with red lead 
into each hole. The intake water pipe, water 
gauge and steam gauge pipe are to be coupled to 
these pipes. 



Making Small Boilers 97 

The Smoke-Box. — Get a cap 5% inches in di- 
ameter, bore a hole 2/4 inches in diameter 
through its center and have it threaded ; also get 
a pipe 2/4 inches in diameter, 3 or 4 inches long, 
for the smokestack and threaded on one end to fit 
the hole in the cap. 

Drill two %-inch holes in the smoke-box cap, 2 
inches from the center of the large hole, when 
the cap will slip over the pipes screwed in the 
smoke-box sheet as shown in Fig. 38. Screw a 
nut on the end of each pipe to hold the cap in 
place and then screw the end of the smoke stack 
into the cap. 

You can make a conical smoke-box, a flanged 
smokestack and a flaring fire-box by turning pat- 
terns of these parts in wood and having them 
cast in brass or iron. A boiler made in this 
way will look better but it will not work any bet- 
ter. 

The Fire-Box. — To make the fire-box take an 
iron, brass or copper ring just large enough to fit 
around the lower cap — I should say fire-box sheet 
— and 4% inches high; drill three or more Vs- 
inch holes at equal distances apart around one 
edge and a like number of %2-inch holes at the 



98 The Boys' Book of Engine-Building 

same distances apart, and thread these latter 
holes with an 8-32-tap. 

Saw, drill or cut out a piece of metal from 
the ring on the end having the screw holes 1 
inch wide and 2 inches long ; this makes an open- 
ing for the fire-box door. To make the door take 
a piece of metal Vs inch thick, i/4 inches wide 
and 2/4 inches long; get a pair of small brass 
hinges and rivet these to the door and to the 
fire-box rings. 

Also saw out with a hack saw, or cut out with 
a cold chisel, an opening on the bottom of the 
fire-box V2 an inch wide and 2 inches long for 
the air draft. 

If solid fuels, such as charcoal, coke and the 
like are to be burned in the fire-box, it must have 
a grate, but if gas, kerosene or alcohol is to be 
used a grate is not needed though each kind re- 
quires a special burner which will be described 
presently. 

The Grate. — To make a grate take a ring of 
iron % inch thick, % inch high and cut seven 
parallel slots % inch wide and %6 inch deep in 
one end and drill four holes through it at equal 
distance so that the grate can be bolted to the 




Making Small Boilers 99 

shell of the fire-box as shown in Fig. 41 ; now cut 
seven strips of either square iron bar or round 
iron rod Vs inch thick and of varying lengths to fit 
the ring and drop these into the slots. The grate 
thus formed will fit inside the fire-box and, once 




Fig. 41. How the Grate is Made 

in, the grate bars cannot slip out. An easier 
way to make a grate is to make a wood pattern 
first and have it cast in iron. 

Gas and Liquid Fuel Burners — An Alcohol 
Burner. — A burner of this kind is shown at A 
in Fig. 42. It will serve the purpose well and 
is the next best thing to a Bunsen burner. It 
can be bought for 25 cents. 

A Gas Burner. — A Bunsen flame burner like 
the one shown at B in Fig. 42, gives a broad, hot 



ioo The Boys' Book of Engine-Building 

flame and is quite expensive, costing as it does 
in the neighborhood of $3.oo. 1 
A Kerosene Burner. — You can make a burner 




Fig. 42 A. An Alcohol Burner 

of this kind with little trouble and at a small 
cost. Cut out of sheet iron a plate Vis inch 
thick and 7 inches in diameter and turn up the 




Fig. 42 B. A Bunsen Flame Stove 

edges Vs inch all the way round to form a pan; 
rivet three legs to it so that it can be set under 
the boiler with the plate at about the height of 

1 L. E. Knott Apparatus Co., Boston, Mass. 



Making Small Boilers 



101 



the grate and tilting toward the back a little as 
shown at C in Fig. 42. 

The next thing to do is to make a hole in the 
bottom of a pint kerosene oil can and solder a cock 




Fig. 42 C. A Kerosene Burner 

to it and in turn solder to this a /4-inch pipe, 12 
inches long; cut a /4-inch hole through the top of 
the door of the fire-box, pass the pipe through 
the hole and over the pan, all of which is shown 
at C. 

Turn on the oil so that it falls drop by drop 
on the pan and let it spread over the whole sur- 



102 The Boys' Book of Engine-Building 

face, then light it and it will burn up with a 
large flame. 

A Good Copper Boiler — The Shell. — To make 
this little upright boiler get a piece of seamless 
copper tube with a %-inch thick wall, 6 inches 
in diameter and ii/4 inches long. Brazed cop- 
per tube is not nearly so good because it might 
expand and pull apart ; if you have to use it, wrap 
a layer of No. 16 Brown and Sharpe gauge steel 
wire around it. 

Or, you can get a sheet of soft rolled copper 
11% inches wide and 20 inches long, form it into 
a cylinder 6 inches in diameter, lap the edges 
over three-fourths of an inch and rivet it. You 
must use large rivets tapering from /4 inch at 
the end to Vie inch at the head. Drill the holes 
in the seam x Yiq inch apart, measured from their 
centers ; put in the rivets and rivet the seam tight. 

Whether you use a drawn copper tube or form 
one yourself, for the boiler sheets, as the ends of 
the boiler are called, use %-inch thick soft rolled 
copper. Cut out two disks from this sheet and 
have one of them 7% inches in diameter for the 
smoke-box sheet and the other one 8% inches in 
diameter for the fire-box sheet. 



Making Small Boilers 103 

Cut out a 1 -inch hole in the center of both 
sheets. Next, hammer the edge of the small 
sheet over % inch all round, thus making a pan 
of it. Likewise bend the edge of the large sheet 
over in the same way 1% inches. When the 
edges of these sheets are hammered into shape, 
each pan must fit snugly into the ends of the 
tube. 

Put the smoke-box sheet in the boiler tube 
first, with the bent edge up as shown in Fig. 38 
and drill a %6-hole through the tube and the rim; 
slip a rivet through the holes from the inside, 
hold a large hammer against its head and with a 
machinist's ball peening hammer, peen the end 
of the rivet, that is hammer it down with the 
ball end until it spreads out evenly all round and 
draws the two pieces of metal together as tightly 
as possible. 

Drill another hole through the rim of the sheet 
and the tube on the opposite side and rivet them 
together to hold the sheet in place. Keep on 
drilling holes with their centers 1:L /i6 inch apart 
all the way round, then slip a rivet into each hole 
and hammer it down. 

Now set the fire-box sheet in the tube with the 



I04 The Boys' Book of Engine-Building 

edge of the rim out and projecting % inch beyond 
the end of the tube, the purpose of which is to 
allow the fire-box ring to be riveted to it as shown 
in Fig. 32. These riveted lap seams should not 
leak steam at a pressure of fifteen or twenty 
pounds but as a precautionary measure you can 
run solder into them. 

The next thing to do is to put in the central 
Hue. This is done in precisely the same way as 
it is in making the iron boiler previously de- 
scribed. The tube should be 1 inch in diameter 
and 8/4 inches long. Be sure that the ends of 
the tube are well expanded and don't forget to 
run solder around the joints before you turn over 
the edges of the tube. 

The Smoke-Box. — If you can get an iron pipe 
cap 5% inches in diameter, making the smoke- 
box becomes a very simple matter. Have a 
steam-fitter bore a 2%-inch hole in the center of 
it, thread it and screw in a piece of pipe 4 inches 
long. The way this is fastened to the smoke-box 
sheet will be explained further on. 

Should you want to make the smoke-box, cut 
out a disk of copper 8 inches in diameter and 
hammer the edge of it over all round making it 



Making Small Boilers 105 

1 % inches wide. Cut a hole 2 inches in diameter 
as before, get a piece of brass or copper tubing 

2 inches in diameter and 4 inches long, thread one 
end of it, screw on a thin brass nut, slip the end 
through the hole in the smoke-box and screw on 
another nut on the other side. 

A conical cast smoke-box with an overhanging 
flange will make the boiler look like the real thing, 
and, if you make a pattern of it and have it cast, 
make a pattern of the fire-box at the same time 
and have it cast in the same metal. 

The Boiler Connections. — All of the fittings of 
the boiler, namely the water intake, the steam 
outlet, the pressure gauge, the water gauge and 
the safety valve, must be provided for while the 
boiler is under construction, that is before the 
sheets are riveted in the ends of the boiler 
tube. 

The way to do this is to drill %-inch holes in 
the tube and smoke-box sheet at the places shown 
in Figs. 38 and 39 ; put a /i-inch pipe, 1 inch long 
and threaded at both ends into each hole; put a 
leather washer on each pipe on both sides of the 
boiler and screw on a nut in and outside. 

The Fire-Box. — This is the lower part of a 



106 The Boys' Book of Engine-Building 

vertical boiler on which the latter rests and in 
which the fire is kept to heat the water. 

There are several ways to make a fire-box, but 
the easiest is to get a piece of brass or copper 
tube the exact diameter of the tube of your boiler 
and 3 inches high. Saw or cut out an opening 
for the door and another for the air draft in 
the manner described for the iron boiler and also 
a door for the former. Now rivet the ring to 
the projecting end of the fire-box sheet as shown 
in Fig. 38. 

If you intend to heat the boiler with a solid 
fuel, you will, of course, need a grate, but if you 
want to use gas or liquid fuels then select one of 
the burners I have previously described for it. 

Fittings for the Boiler. — Screw a stop-cock on 
to the water intake pipe; a hand or a power 
force pump, or an injector must be coupled to 
the stop-cock and to a can of water or other 
source of water supply. 

Screw an elbow on to the outlet steam pipe, 
screw a i-inch length of pipe into the elbow and 
screw a stop-cock to the end of the pipe; screw 
a 2-inch length of pipe into the other end of the 
stop-cock, screw on an elbow and then screw 



Making Small Boilers 107 

another length of pipe into the elbow long enough 
to reach to the engine. 

You will need an elbow screwed to the pipe 
for the pressure gauge and, finally, if you have 
a steam whistle, screw a coupling on the pipe in 
the smoke-box sheet. Pipe /4 inch in diameter 
can be bought cut to any length up to 2 feet and 
threaded on both ends, and the elbows and coup- 
lings are tapped with right-left-handed threads 
to fit the pipe. The boiler complete with a cast 
smoke-box and fire-box is shown in Fig. 43. 

How to Test the Boiler. — Before you get up 
steam in the boiler after you have completed it, 
the safest way is to test it by trying it with 
water pressure. Then you can find out where it 
leaks and why without danger either to yourself 
or to your handiwork. 

If you will turn to the next chapter, you will 
find that the steam gauge is constructed with a 
bent tube so that instead of the steam acting di- 
rectly on the mechanism of the steam gauge the 
tube is filled with water and the steam presses 
on the water instead. 

Hence all you have to do is to connect the 
intake water pipe to a force pump and to pump 




Fig. 43. The Boiler Complete 
108 



Making Small Boilers 109 

until the pressure gauge indicates twice the num- 
ber of pounds pressure that you ever intend to 
get up in steam. The boilers described in this 
chapter should be tested to 40 or 50 pounds pres- 
sure ; consequently you should never let the steam 
pressure rise to more than 20 pounds. 

A Safe Way to Operate a Small Boiler. — 
Any engine that will run with steam can be run 
with compressed air. 

Now by pumping air into the boiler until it is 
under as much, or a little more pressure than 
steam, if you used it, you can run your engine 
without steam and, naturally, without fire, and 
this eliminates both of these elements of danger. 

To pump up the boiler is a simple matter, 
for you can do it with a bicycle pump, or, better, 
with a motor car pump. If you use compressed 
air, you do not need the water gauge on the 
boiler; instead of coupling a source of water to 
the intake pipe fit a bicycle valve or an inner tube 
valve — which is often thrown away or one can 
be bought at an auto supply house — in the intake 
pipe and then connect the latter with the pump. 



CHAPTER VI 
FITTINGS FOR MODEL ENGINES 

Pipe and Fittings — Taps and Stopcocks — The Steam 
Whistle — Safety Valves: The Lever Safety Valve; A 
Spring, or Pop, Safety Valve — The Governor — A Steam 
Force Pump — The Injector: How to Make It; How It 
Works — The Water Gauge — The Steam Gauge: How 
to Make It; Calibrating the Dial. 

In building model engines, especially steam en- 
gines, a large number of fittings such as pipe, 
unions, or pipe couplings, stop-cocks, whistles, 
safety valves, governors, force pumps, water and 
steam gauges are needed. 

While it is usually more convenient to buy 
them ready-made of the right size to put on your 
engine, or boiler, it may happen that you would 
rather make them yourself and so I'll tell you 
how. 

Pipe and Fittings. — You can buy brass tubing 

of any size you want from Viq inch in diameter 

on up and cut to any length you may need, but 

it is not always an easy matter to get couplings, 

no 



Fittings for Model Engines 



III 



elbows, T's and crosses that are threaded to fit. 
The Weeden Mfg. Co., of New Bedford, 
Mass., sells pipe and fittings in small sizes, 
threaded and ready to use ; you can buy brass or 
copper tubing in nearly all sizes from Patterson 
Brothers, 2j Park Row, New York City, and 



P/PE 



) !~ 



COUPLING 





ELBOW 




CROSS 

Fig. 44. Steam Pipe Fittings 



elbows, T's and crosses made of brass Vs inch 
and %e inch in diameter are sold under the name 
of brass sockets by the Ideal Aeroplane and Sup- 
ply Co., 82-86 West Broadway, New York City, 
and the Wading River Mfg. Co., Wading River, 
Long Island, N. Y. 

Regular steam pipe and fittings like those 
shown in Fig. 44 can be bought in % inch and 



112 The Boys' Book of Engine-Building 

%6 inch sizes, outside diameter, of Luther H. 
Wightman and Co., 132 Milk Street, Boston, 
Mass., and the Chicago Model Works, 166 West 
Madison Street, Chicago, 111. 

Taps and Stop-cocks. — A small brass tap or 
stop-cock half size shown at A in Fig. 45 can be 
bought for 50 cents, a larger one for 65 cents and 
a still larger one for 75 cents. 

A good way to make a stop-cock is to cut off 

H °PLUQ MN DLE 



czQti 




Plt/G BODY 



Fig. 45. A Brass Stop-cock. (Full Size.) 

a piece of brass rod the size you want it and drill 
a hole through it from end to end, the diameter of 
which should be about half the diameter of the 
rod. 

Next drill a plug hole for the plug through the 
middle of the stop-cock body as shown in the 
cross section drawing at B in Fig. 45, ream it out 
to make it slightly conical, and drill a hole 
through the body opposite the plug hole for a 



Fittings for Model Engines 113 

screw. The plug, which is a conical piece of 
brass, must fit into the plug hole nicely and have 
a hole drilled through it as is also shown at B. 
Drill a %6-inch hole in each end and thread 
them. 

The next operation is to grind the plug to make 
it fit the plug hole steamtight ; to do this make a 
grinding paste of fine emery mixed with a few 
drops of sewing machine oil and thinned down 
with kerosene. Rub the mixture on the conical 
edge of the plug, then set the plug in the plug 
hole and turn it around forth and back but don't 
press too hard on it. 

When the plug is seated, as it is called, push a 
screw through the body of the stop-cock and 
screw it into the bottom of the plug. Now make 
a handle for it and screw it to the top of the plug 
and your stop-cock is done. 

The Steam Whistle. — The kind of a steam 
whistle used on a locomotive is called a bell whis- 
tle because it is fitted with a hollow top closed 
at the upper end and which somewhat resembles 
a bell. 

The first thing you need to make a steam 
whistle with is a stop-cock like the one just de- 



H4 The Boys' Book of Engine-Building 



scribed. For a whistle of the right size for a 
model locomotive make a stop-cock of a piece of 
rod having an outside diameter of Vs inch and 
drill a %6-inch hole through it. 

Drill a /46-inch hole clear through one end of 
the plug body and another at right angles to it, 




PLUGEND 
SOLDER HERE 

B£IL 




OUTLET MOUE 
CUP 

STOPCOCK 
MJfflDlF 

Fig. 46. The Steam Whistle 

so that the end will have four outlet holes for 
the steam to escape through. Put the plug in 
the middle of the body as before and thread both 
ends of the latter. 

Make a cup of a disk of brass %6 inch thick 
and % inch in diameter and hollow out one side 
as shown in the cross-section at A in Fig. 46, 



Fittings for Model Engines 115 

either with the point of a large drill or with a 
countersink. Drill a %2-inch hole through it and 
thread it to fit the end of the stop-cock body; 
screw the cup on the end with the concave, that 
is the hollow part up, and screw it down far 
enough so that the holes in the end of the tube 
are just above the hollow of the cup. 

Cut out a disk of sheet brass %2 inch thick and 
% inch in diameter, drill a %-inch hole through 
the center of it, thread it and screw it to the end 
of the stop-cock body so that it sets flush with 
the edge of the cup. Now thread the inside of 
the end of the body and screw in a brass rod %2 
inch thick and % inch long but not in far enough 
to stop up the outlet holes in the end of the stop- 
cock. 

For the bell of the whistle cut off a piece of 
brass tube % inch in diameter and % inch long; 
make a plug end for it of a piece of brass rod 
and either screw, or solder, it into one end ; drill 
a Vi e-inch hole through it and thread it; then 
thread the end of the brass rod and screw the 
latter into it and, finally, put a nut on the end to 
hold the bell on tight. The lower edge of the 
bell should come within Vig inch of the edge of 



n6 The Boys' Book of Engine-Building 

the cup. By screwing the bell up or down you 
can adjust it so that it will whistle the loudest. 

Now when the handle of the stop-cock is 
turned on, the steam rushes out of the holes in 
the end of the body; this fills the hollow cup 
under the disk when it is forced out and up 
against the edge of the bell; on striking it the 
bell is set into violent vibration and a character- 
istic steam whistle results. 

Safety Valves. — There are several kinds of 
safety valves but I shall describe only two of 
them and these are: (i) the lever safety valve 
and (2) the spring safety valve. 

The Lever Safety Valve. — The time-honored 
lever safety valve is largely used on stationary 
boilers. The easiest way to make a safety valve 
of this kind is to take a /4-inch pipe, 1 inch long, 
and thread both ends of it. 

Cut or saw out two brass disks each %e inch 
thick and % inch in diameter; drill a %6-inch hole 
through one of them and thread it to fit the pipe ; 
drill a % 6-inch hole through the center of the 
other disk and make it %6 inch in diameter on 
the other side. 

Put the two disks together and drill a %2-inch 



Fittings for Model Engines nj 

hole on each side of the holes in the center and 
thread them; screw the disks together on one 
side and then make a standard of a piece of brass 
rod Ys inch in diameter and % inch long; thread 
one end, drill a % 6-inch hole through the other 
end and saw a slot Vie inch wide and %e inch 
deep in it ; these things done, screw the standard 



G&oovi 



: SZ0HM& 
VPPEJtDJS* 



W 



& 







BRASSPM 



Fig. 47. A Lever Safety Valve 




through the disks as shown at B in Fig. 47 and 
screw the disks together on the other side. 

Make a lever M.6 inch thick, Vs inch wide and 
2% inches long; drill a hole in one end of it and 
set the end of the lever in the slotted end of the 
standard and pivot it with a pin. 

The plug can be made of lead, type metal or 
brass; it must be a shade larger than % inch at 
the bottom and a trifle larger than %6 inch at 
the top. If it is made of lead, or type metal, 



n8 The Boys' Book of Engine-Building 

you can fit it into the valve hole steamtight by 
pressure and turning it around, but if it is of 
brass you will have to grind it with fine emery 
mixed with oil. 

Drill a /46-inch hole through the center and 
push a brass wire % inches long and threaded on 
both ends through it; screw a nut on both ends 
and file a groove in the top end of the wire so 
that the lever will rest in it. 

All that is left to be done is to make the weight ; 
this can be a piece of rod V2 inch in diameter and 
% inch long; saw a slot Yi6 inch wide and /4 inch 
deep and put a pin through the upper end. Slip 
the weight on the lever and screw the safety valve 
into the boiler shell. 

A Spring or Pop Safety Valve. — A spring or 
pop safety valve is used on locomotives and you 
can easily make one for your model. If you will 
take a look at Fig. 53, which shows a cross-sec- 
tion view of the locomotive boiler, you will see 
that the safety valve pipe which leads through 
the steam dome outside is Vs inch in diameter and 
the end of this pipe must be threaded. 

Cut out a disk % inch in diameter and Vs inch 
thick; drill a %2-inch hole through its center and 



Fittings for Model Engines 



119 



thread it to fit the pipe. Cut out another disk 
of the same thickness and size, drill a %-inch 
hole in its center and ream it out until it is % 6 
inch in diameter on the other side. Make and 
grind a brass plug to fit this conical hole as shown 
in Fig. 48. 

BLOW OFF 
HOLE 

ROD 



* 






J.JB 




SPRING 

PLUG 

P/5K3£/?T 

DISK 



Fig. 48. A Spring or Pop Safety Valve 



Fit both of these disks into one end of a pipe 
Vie inch in diameter and % inch long with the 
valve disk inside, and solder both of them in the 
pipe. Put the plug in the valve hole; form a 
spiral spring of brass wire and put it in the pipe 
on top of the plug; thread the inside end of the 
pipe and thread a rod /4 inch long to fit it; drill 



120 The Boys' Book of Engine-Building 

a %-inch hole through the rod from end to end 
to let the steam escape when the valve is opened, 
and cut a slot across one end of this plug and 
then screw it into the end of the pipe. 

The action of this safety valve is simple 
enough: When the pressure of the steam is 
higher than it should be it forces the plug up 
against the pressure of the spring and the steam 
blows off through the hole in the screw plug at 
the top of the safety valve. 

The Governor. — A governor is used on sta- 
tionary engines where it is necessary for the 
speed to be constant, that is perfectly steady. 

The usual kind of governor works on the prin- 
ciple of centrifugal force , that is two balls, each 
of which is fitted to the end of a lever, are made 
to revolve by the engine ; as the speed of the en- 
gine increases the balls fly apart and raise the 
levers. The levers are in turn connected to the 
throttle valve and when the speed is great enough 
the raising levers close the valve, the steam is 
shut off and the speed of the engine is reduced. 

To make a centrifugal governor, or ball gov- 
ernor, or fly ball governor, as it is variously 
called, get a soft steel rod Vs inch in diameter 



Fittings for Model Engines 12 1 

and 2V2 inches long for the spindle; file one end 
of it flat and drill a % 6-inch hole through it as 
shown at A, Fig. 49. 

Cut two strips of brass Viq inch thick, %6 inch 
wide and V2 an inch long for the top bars; lay the 
bars together and drill a /^6-inch hole through 
them at both ends and in the middle; put a bar 

TOP3/J/Z 

f fT m 



CQNTROL 



1 



PULLEY 



9 *»•«• — — . — 1— J 




TO^ THROTTLE 

STBAriCHEST 



/I 

Fig. 49. An Easily Made Governor 



on each side of the flat end of the spindle and 
drive a pin through all of them, tight. 

Make two fly arms of %2-inch brass or steel 
rod, % inch long; thread one end of each one and 
file both of them a little flat in the middle and at 
the plain ends and then drill a Yi 6-inch hole 
through the middle and ends. 

Next cut out four flat control arms Viq inch 
thick, %e inch wide and % inch long; lay all of 



122 The Boys' Book of Engine-Building 

the arms together and drill a hole through the 
ends of them. Set the ends of a pair of them 
on the opposite sides of the fly arms and pivot 
them with pins so that the joints will move freely. 

The next thing is the guide. Turn or file 
down a rod % inch in diameter and V2 inch long, 
and drill a hole % inch in diameter through it 
from end to end so that it will slide easily on the 
spindle; cut or file a groove, Vs inch wide Vs inch 
from the one end; file down the opposite sides 
of the other end and drill a hole through each 
side. 

Slip the guide on the spindle and joint the 
flat sides of it to the lower end of the control 
arms on each side. Screw a ball % inch in diam- 
eter to the free end of each of the fly arms and 
then fix a grooved pulley V2 inch in diameter on 
the spindle. 

Make a lever of a strip of ^6-inch brass %6 
inch wide and 1% inches long, and drill a hole in 
each end and a third hole V2 an inch from one 
end as shown at A. Cut out two strips of brass 
each % inch long of the same thickness and width 
as the lever; drill a hole in one end of the lever 
between them and rivet the three pieces together; 



Fittings for Model Engines 123 

now bend the ends out until they fit into the 
groove of the guide. 

The free end of the lever is pivoted to another 
and shorter lever and this in turn is pivoted to an- 
other and a still shorter lever and this latter lever 
is pivoted in turn to the handle of the stop-cock, 
or throttle, as it is called when it is used to open 
and close a steam pipe, all of which is shown in 
Fig. 49. 

Finally, the lower end of the spindle must rest 
in a bearing and turn easily, and the grooved 
wheel is belted to the pulley on the crankshaft of 
the engine. 

Now when you turn on the steam the balls are 
down and the throttle is open ; as the engine gets 
up speed the balls fly apart, this pulls the guide 
up and so raises the yoked lever; this shuts off 
the steam until the speed falls off when the balls 
begin to drop and more steam is admitted to the 
engine. A bought governor is shown at B. 

A Steam Force Pump. — For stationary boilers 
a steam force pump is generally used to pump 
water into it as needed. 

A simple force pump can be made of a couple 
of check valves, as shown at A in Fig. 50, that 



124 The Boys' Book of Engine-Building 

is valves which let the water flow through them 
in one direction only. You can make these 
check valves or buy them ready-made. 

If you make them, buy two %6-inch elbows, 
and two pieces of pipe V2 inch long, all of 




PISTON 



PLUNGER, 



JLJf" 



P/PE /TOINTflKE 
OFBOILER 
8/PLL 





—ELBOW 



\*P/PE f p/p E 
TO THE 

WATER B 

SUPPLY 

Fig. 50. A Steam Force Pump 



which are threaded at both ends ; also get a piece 
of pipe 2 inches long and thread it on one end. 

Cut out two disks Me inch thick and let them 
be of the exact diameter of the inside of the el- 
bows; drill a %-inch hole in the middle of each 
one and solder it in one end of the elbow just 
below the threads; this can be done by putting 



Fittings for Model Engines 125 

some soldering fluid around the edge of the disk 
inside the elbow, heating it in the flame of an 
alcohol lamp or a Bunsen burner and touching 
it with the end of some wire solder. 

Drop a brass ball * %2 inch in diameter in each 
elbow on top of the hole ; screw one of the /4-inch 
lengths of pipe into one of the elbows above the 
ball and far enough in so that the ball can't roll 
out. Screw the end of the pipe that goes into 
the boiler into the other elbow above the ball 
which will prevent it from coming out. 

Screw the other /4-inch length of pipe into 
the other end of the elbow and then couple the 
elbows together by screwing the T's to the ends 
of the pipes and screw the 2-inch length of pipe 
to the third opening of the T. 

Finally, make a close fitting brass piston for 
the pipe, or rather the cylinder, as it is now called, 
all of which is clearly shown at B in Fig. 50. 
The piston can be worked by hand, it can be 
coupled to a separate eccentric on the crankshaft 
or it can be connected to a crank which is driven 
by the engine. Of course it must be used in 

1 Can be bought of Patterson Brothers, Park Row, New York 
City. 



126 The Boys' Book of Engine-Building 

an upright position. A small force pump as 
shown at C can bought for $3.5o. 1 

It works like this : When the piston is raised 
it pulls the air out of the check valves ; this pulls 
the ball in the right hand valve down tighter, 
but it lifts the ball in the left hand check valve 
and hence the air and water in the pipe under 
it is raised up into the barrel in which the piston 
works. 

When the piston is forced down, the pressure 
of the water presses the ball in the left-hand 
check valve down tight, but it pushes the ball 
in the right-hand valve up and this allows the 
water to pass through it and into the boiler. 

The Injector — How to Make It. — To feed 
water into a steam boiler without having to pump 
it an injector is used. While nearly all station- 
ary boilers are fitted with pumps, locomotive boil- 
ers are provided with injectors which have no 
moving parts. 

An injector is so made that steam from the 
boiler is forced through a nozzle, thus forming 
a jet, and blows the water into the boiler against 

1 Can be bought of Luther H. Wightman, Boston, or of the 
Chicago Model Works, Chicago. 



Fittings for Model Engines 127 

its own pressure. Hence we have what is called 
a hydrostatic paradox. 

Get a piece of pipe % inch in diameter and 2 
inches long, thread both ends of it and drill a 
/4-inch hole in the pipe V2 inch from one end for 
the overflow pipe. Fit a cap to each end of the 
pipe, drill a /4-inch hole through the center of 
each one and thread them to fit a %-inch pipe; 
these are for the steam nozzle and the valve 
chamber as shown in Fig. 51. 

Next you will need an elbow that will fit a 
%-inch pipe and a piece of pipe % inch in diameter 
and /4 or 1 inch long and threaded at both ends 
for the overflow pipe. 

Now make the nozzles and this is no easy job 
either way you do it. The first way is to take a 
brass rod % inch in diameter and cut off three 
pieces ; have one of them 1 inch long, the second 
1/4 inches long and the last 1% inches long. 

Drill a /4-inch hole, V2 an inch down in the end 
of each piece, and a /46-inch hole the rest of the 
ways through; then ream out the holes to form 
conical chambers in them. File, or, better, turn 
down in a lathe, the ends of the nozzles to give 
them a conical form. 



TO STEAM 
IN BOILER 



STEAMHOZZ 

TO WATElt 
TANK 

ELBOW 
CAP 

FEED 
WATER//OZZIA 
SMELL 



VALVE 

CHAMBER 
OVER-— ***** 
FLOW 

PIPE 



PLUG VALVE 
R/NG 




STEM 



TO WATER. 
INBOJLER 

Fig. 51. Cross-section of a Steam Injector 



128 



Fittings for Model Engines 129 

Another and easier way is to shape up the 
nozzles of K6-inch sheet copper and hard solder 1 
the seams. Whichever way you make them 
thread the large ends of the nozzles. This done, 
make a conical plug that will fit into the valve 
chamber, screw a stem into it and set it into the 
lower end; put in a ring with the hole over the 
stem and solder it there. 

Having finished all the parts of the injector 
the next thing is to assemble it. Screw the feed 
water nozzle into the cap; screw the elbow T on 
the end of the nozzle and then screw the steam 
nozzle into the elbow so that the small hole in it 
is just inside the large hole in the feed water 
nozzle. Screw the valve chamber nozzle into 
the end of the other cap ; screw both caps on the 
large pipes and, finally, screw the overflow pipe 
into the shell. 

Now, couple the steam nozzle to the boiler 
above the water line, connect the valve chamber 
to the boiler below the water line and join the 
elbow to the water tank. When all these things 
are done, if you have not less than forty pounds 
of steam in the boiler, the pressure of the steam 

1 Borax mixed with water to the consistency of paste. 



130 The Boys' Book of Engine-Building 

in the boiler will force the water into the boiler 
against the back pressure and this is called a 
hydrostatic paradox. 

How it Works. — When the steam flows into 
the steam nozzle it blows out of the small end 
in a jet and on down through the feed water 
nozzle — that is, it does so at first. 

The jet of steam forms a vacuum in the elbow 
and this pulls the water at a high rate of speed 
into the feed water nozzle and this, together with 
the force of the steam striking the water, drives 
the latter through the end of the feed water noz- 
zle in a jet and into the valve chamber and since 
this is an inverted nozzle the steam expands. 

Now when steam expands it loses in speed and, 
consequently, it gains in pressure until, at the 
lower end of the valve chamber, the pressure is 
so high it can pass into the boiler through the 
check valve, which opens only in the direction 
the stream is going. 

The purpose of the overflow pipe is to allow 
the injector to get started and the water and 
steam escape through it. 

The Steam Gauge. — It is a hard job to make a 
small steam gauge that is accurate and though 



Fittings for Model Engines 131 

I shall tell you how to make one and calibrate 
it, that is to mark the scale so that it will show 
the steam pressure of the boiler in pounck^, my 
advice is to buy one of some reliable maker. 

This kind of a steam gb&gt is known as a 
Bourdon gauge for the reason that it was first 
made by Bourdon, an instrument maker of Paris. 
First form a ring of %2-inch thick sheet brass, 
V2 an inch wide and % inch in diameter ; make a 
butt joint and solder it and drill a ^6-inch hole 
through the ring close to the joint. 

Cut out two disks of sheet brass Vs2 inch thick 
and 1 inch in diameter for the front and back 
of the gauge. Drill three holes through them 
with their centers % inch from the edges and at 
equal distances apart; in the one to be used for 
the back drill two more holes in a line from the 
center and have each one % inch on each side 
of the center; drill a /46-inch hole in the center 
of the other disk which is the front one. 

Make a pattern for the spring box, that is the 
hollow base which contains the pressure plate 
and the coiled spring, and have it cast. The 
pattern should be made in two pieces, curve the 
top part to fit the ring and hollow out the under 



132 The Boys 9 Book of Engine-Building 

part of it. Also hollow out the upper part of 
the bottom of the box and you will observe that 
both the top and the bottom have lugs on them. 

When you get the castings, file them up and 
drill a %2-inch hole through the curved ends of 
the top ; then drill a hole in each of the lugs and 
thread it for a screw and drill a Vi 6-inch hole 
through the center of the box for the pressure 
rod to pass through. 

Drill a hole in each of the lugs of the bottom 
part of the box, but do not thread them, and, 
finally, drill a % 6-inch hole through the center 
of it and thread it to fit a /4-inch pipe. 

Now for the works: make an angle support 
of a strip of brass %2 inch thick, % inch wide 
and 1% inches long; bend the edges as shown at 
B in Fig. 52 so that it stands % inch high; drill 
a hole in each end so that it can be screwed to 
the back; drill a hole in the center for the pin, 
or arbor as it is called, on which the pinion, that 
is a little cogwheel, is fixed inside the case and 
to the end of which the needle or pointer is 
screwed outside the case. Drill another hole %2 
inch below the center and %2 inch to the left of it 
for the pin on which the toothed wheel turns; 



Fittings for Model Engines 133 

and, lastly, drill a hole at the top and to the left, 
put in a pin and fix a flat spring to it. 

Get a piece of pinion wire, 1 that is a ribbed 
wire used by clockmakers for making small pin- 
ions, or toothed wheels of any length, and cut 
it off Vs inch long, or you can use a small pinion 



SUPPORT 
TOOTHEP 



COMPRESS 

SP/ZAL 

SPRING- 
lug 

BR/tSS 
PL/PTE 




£/)CK~ 



ii 



NEEDLE 



CFRONT 
PLATE 



RING ORD/4L 



SIPHON 






flT£H 



Fig. 52. How a Steam Gauge is Made 

taken from an old clock. Set it on a steel wire 
Vie inch thick and %e inch long, thread both ends 
of the wire, or arbor, push the short end through 
the support and screw on a nut ; and see to it that 
it runs very true. 

Take another clock wheel, or buy a new toothed 

1 Can be bought of dealers in model makers' supplies. 



134 The Boys' Book of Engine-Building 

wheel %6 inch in diameter, drill a hole in two of 
the spokes % inch from the center and fix a pin 
in each one of them. To make the pressure rod 
sharpen one end of a piece of He-inch wire % 
inch long; flatten the other end and drill a hole 
through it, and also flatten it at a point Vie inch 
above the pointed end, drill it and fix a bit of 
wire in it for a stop for the spring. Now pivot 
the connecting rod to the toothed wheel and slip 
the rod through the hole in the bottom of the 
ring; then pivot the wheel to the support and 
screw the curved top of the spring box to the 
ring. 

Next cut a piece of brass Vi6 inch thick, % inch 
wide and %6 inch long; round off one side of it 
with a file and make a dent in the center of the 
flat side of it with a center punch. Cut off a 
piece of thin rubber V2 inch wide and % inch long ; 
lay it on top of the lower part of the spring box 
and set the rounded brass plate in the middle of 
it with the flat side up. 

Slip an open spiral spring over the pointed end 
of the rod, fit the bottom part of the spring box 
to the top, being sure that the pointed end of 
the pressure rod sets in the dent in the brass 



Fittings for Model Engines 135 

plate and screw the top and bottom of the spring 
box together tight. 

Set the ring on the back plate ; put the front 
plate on the ring with the arbor sticking through 
the hole and then bolt the two plates together. 
Make an index needle, or hand, of a bit of wire 
% inch long, flatten it, drill a hole %6 inch from 
one end and fix it on the end of the arbor. A 
minute hand from a watch makes a good needle. 

Thread the ends of a piece of brass pipe Vs 
inch in diameter and 2% inches long; cork up 
one end and fill it with melted lead; when it is 
cold, bend the pipe into the shape of a U but with 
one end longer than the other end by % inch; 
heat the bent pipe, or siphon as it is now called, 
until the lead melts and let it run out. Now 
screw the long end of the siphon into the boiler 
above the water line, of course; fill the siphon 
with water and screw the gauge to it. 

Calibrating the Dial. — To calibrate the gauge 
you have made, that is to graduate the face of it, 
or dial as it is called, you must borrow an accu- 
rate gauge and fix it in the boiler together with 
your own. 

As the pressure rises in the boiler you simply 



136 The Boys' Book of Engine-Building 

mark your dial according to what the needle 
shows when it is compared to the first-rate gauge 
and that is all there is to it. 
The Water Gauge. — To keep the boiler from 



THISEND 
SCREWS 
INTOBOI, 

RUBBERt-OCK- 
NUT 




LOCH 



NUT 



■ELBOW 



RUBBER 
WASHER 

LOCKNUT 



GLASS 
TUBE 



&-' 



TH/SENDF^ 52 - 
SCREWS 

INTO 
BOILER 



S55S 



^wvs^, 







L RUBBER. 
WASHER 



-ELBOW 



Fig- S3- Cross Section of a Water Gauge 



blowing up for the want of water, you must fit 
it with a water gauge. This is a piece of glass 
tubing set into two elbows, one of which is 



Fittings for Model Engines 137 

screwed into the boiler below the lowest level 
the water ought to be allowed to get, and the 
other one is screwed into the boiler above the 
highest level at which the water ought to stand. 

To make a water gauge for the boiler take two 
% 6-inch elbows and fit each one with a lock nut 
as shown in Fig. 53. Get a length of thick 
glass tubing for the water glass with an outside 
diameter just large enough to fit the inside of 
the lock nuts and elbows. 

Next fit a thick rubber washer into each lock 
nut and slip the lock nuts on the tube. Put the 
ends of the tubes into the top and bottom elbows 
and then screw the nuts on them tight. The 
pressure of the lock nuts on the rubber washers 
will expand them, that is squeeze them out, and 
press them against the tube hard enough to make 
them steam-and-water-tight ; at the same time it 
is easy to replace the glass tube should it get 
broken. , 



CHAPTER VII 
A MODEL ATLANTIC TYPE LOCOMOTIVE 

The Parts of a Locomotive : The Boiler : The Shell, 
The Smoke-stack, Bell, Sand Box and Steam Dome, The 
Saddle, Pedestal and Hanger, The Front Tube Sheet, The 
Steam Pipe and Throttle Valve, The Back Tube Sheet, 
The Crown Sheet, The Boiler Tubes, The Fittings — 
Making a Cardboard Model. 

An Atlantic, or 4-4-2, type of locomotive as it 
is called by railroad boys, is one that has four 
small, or truck wheels in front, four driving 
wheels and two trailing wheels. It is a type of 
locomotive much used in the East for hauling 
fast passenger trains. 

To make a model Atlantic type of locomotive 
that will look like a real one will not only take a 
lot of your time, but you will need a deal of pa- 
tience, a fair skill in using tools and considerable 
cash to boot, but whatever time, trouble and* ex- 
pense you are put to you will feel repaid a hun- 
dred fold when you have it completed and in 
running order. 

138 



A Model Atlantic Type Locomotive 139 

As in the case of the horizontal engine there 
are two courses open to you in building this loco- 
motive and these are, (1) to make the patterns 
yourself and have them cast, and (2) to buy a 
complete set of castings and finish them up. My 
advice is to build the locomotive from the ground 
up, because when it is all done, it is really yours; 
on the other hand it will be much easier to buy a 
set of castings as each piece is cast exactly to size 
and shape. 

To picture and describe each part in detail as 
I did the horizontal engine would take a whole 
book the size of this one, but after you have made 
the horizontal engine and the copper boiler which 
I told you about in the chapters that have gone 
before, you will have small trouble in building 
this model locomotive. 

So that everything may be clear to you I have 
made scale drawings of the boiler and the engine 
and these will enable you to work intelligently, 
especially if you will follow the directions to the 
letter. One more thing, in reading the drawings 
just remember that a dotted line usually repre- 
sents a part which is back of some other part 
and hence cannot really be seen. I have also 



140 The Boys' Book of Engine-Building 

used dotted lines to indicate the limits of meas- 
urements and sometimes to show where a piece 
of metal is to be bent. 1 

The Parts of a Locomotive. — Every locomo- 
tive, however large or small, is made up of the 
following main parts: 

(1) The boiler 

(2) The engine 

(3) The pilot, or cowcatcher and 

(4) The cab 

The tender is an entirely separate, though none 
the less necessary, adjunct for it has a coal bunker 
and a water tank which supplies fuel and water 
to the locomotive. 

The Boiler. — This boiler is of the horizon- 
tal tubular type and, like every other boiler, it 
consists of (a) the boiler proper, (b) the smoke- 
box on the front end and (c) the fire-box on the 
rear end. 

A modern locomotive boiler is made a little 
differently from the ordinary horizontal station- 
ary boiler, and this makes it necessary to put 
the parts together in the order I have given. 

1 In engineering drawings only those lines that represent some- 
thing that cannot be seen are dotted and all other lines are solid. 



A Model Atlantic Type Locomotive 141 

The Shell. — Get a seamless copper tube with 
a wall l Vs inch thick, 3% inches in diameter and 
1 6/4 inches long; this forms the shell, as the out- 
side of the boiler is called. Saw out one end of 
the tube, or shell, 1% inches deep and 5% inches 
long as shown at A in Fig. 54. This done, drill 
three rows of holes around the shell so that the 
sheets can be riveted to it later. Drill the first 



<S?Atf 









U wun «?#-■ " - */ [ TH£ BO/LPD sue. ^6 FOR 

Fig. 54. The Boiler Shell 

row of holes 3% inches from the front end of the 
boiler, drill the second row 5% inches from the 
back end and drill the last row % inch from the 
back end. Four holes only need be drilled % 
inch from the front end as the smoke-box sheet 
is screwed to it instead of riveted. 

Drill a hole for exhaust steam pipe and 
drill or cut out two holes in the top of the 
shell for the smokestack and the steam dome; 

x The wall is the thickness of the metal of which the tube is 
made. 



142 The Boys' Book of Engine-Building 

make the hole for the stack V2 inch in diameter 
and have its center 1% inches from the front, and 
the one from the steam dome 1 Vs inches in diam- 
eter and have its center 6V2 inches from the back 
end of the shell, all of which is shown in Figs. 
54 and 55. 

The Smokestack, Bell, Sand Box and Steam 
Dome. — The next thing to do is to make and 
rivet the smokestack, the sand box, the bell frame 
and the steam dome to the top of the shell as 
shown in Fig. 55. This is a cross-section view 
of the whole boiler and it will give you all the 
dimensions you need that are not shown in Fig. 

54. 

The easiest way to get a real looking smoke- 
stack, sand box and steam dome is to make pat- 
terns of them and have them cast in iron, then 
file them up and give them a coat of black enamel. 

The smokestack should be % inch in diameter 
at its base with a flange on it % inch wide, have 
a top 1 inch in diameter and be 1% inches high. 
Make the sand box 1% inches in diameter, with a 
%-inch flange on the bottom, and i34 inches high; 
bore a hole % inch in diameter in the top and 
fit a cover in it. A hole on each side Vs inch in 




*43 



144 TJie Boys 9 Book of Engine-Building 

diameter near the bottom of the box can be 
drilled in the casting when you get it. These 
are for the sand pipes. 

It's a hard job to make a pattern for the bell 
and have it cast, but you can buy a bell and make 
a frame for it. The steam dome is i% inches 
in diameter and 1Y2 inches high. Drill two %- 




THE hWGEfZ^J^fr 



THE PE&E9TM 
Fig. 56. The Saddle Pedestal and Hanger 



inch holes on opposite sides of the dome as shown 
at A in Fig. 55; one of these is for the steam 
whistle and the other for the safety valve. The 
dome must, of course, have a wide flange so that 
it can be riveted securely to the boiler shell. 

The Saddle, Pedestal and Hanger. — The next 
thing to do is to make the patterns for the cylin- 
der saddle, the driving wheel pedestal and the 
hanger for the trailing wheels. These are shown 
at A, B and C in Fig. 56 and the dimensions are 



A Model Atlantic Type Locomotive 145 

marked on them. Drill two holes through the 
saddle, four through the pedestal and two through 
the hanger so that they can be riveted to the 
boiler shell and fire-box as shown at A in Fig. 

55. 

Drill four holes through the hangers of the 

pedestal to form the bearings for the axle for 

the driving wheels and drill two holes in the 

ends of the hanger of the trailing wheels to form 

bearings for its axle. 

When you have done all these things, smooth 
up the castings and then bolt the saddle to the 
under side of the boiler with its center 1% inches 
from the front end, see A, Fig. 55 again. Bolt 
the pedestal to the boiler in a line with the saddle 
and with its center 8% inches from the front end. 
You must screw these bolts up tight or else the 
boiler will leak. 

The Front Tube Sheet. — Now make the front 
tube sheet, as shown at A in Fig. 57. Cut out a 
disk of sheet copper Vs inch thick and 4% inches 
in diameter and hammer the edge of it over all 
round to form a flange % inch wide, when the 
sheet will just fit into the boiler. 

This done, drill eight /4-inch holes through the 



146 The Boys' Book of Engine-Building 

lower part of it for the boiler tubes, though you 
can have fewer tubes if they are larger; drill 
another hole i%6 inch in diameter through the 




€'/8 



6/?C/f TUBE SHEET FRONTTUBE SHEET 



CROW* SHEET 
Fig. 57. The Front Tube, Back and Crown Sheets 

upper part of the sheet for the steam pipe. Rivet 
the sheet to the shell 3% inches from the front 
end of the boiler, as shown in Fig. 55. 

The Steam Pipe and Throttle Valve. — The 
steam pipe, which carries the steam from the 
steam dome, through the front tube sheet, then 
branches out into two pipes, and each one passes 
out of the smoke box on the side where it joins 
its respective cylinder; it is 5%e inches in diam- 
eter and 7% inches long and threaded at both 
ends. 

Bend the pipe as shown in Fig. 55 and screw 
a small stock-cock described in the previous chap- 
ter — on one end for the throttle valve; screw 
or otherwise fix a handle to the valve % inch long 



A Model Atlantic Type Locomotive 147 

and pivot a throttle rod %2 inch in diameter and 
7 inches long to the valve handle. 

Screw a nut on the free end of the pipe, 1 inch 
down, push the end of the pipe through the hole 
in the front tube sheet and then screw another 
nut on the other side of the sheet ; finally, screw 
a T on the end of the pipe. The throttle valve 
should now be in the center of the steam dome 
for it is here that the hottest steam generated by 
the boiler gathers. 

The Back Tube Sheet. — Next cut out the back 
tube sheet as shown at B in Fig. 57 and make 
it the same size as the front tube sheet. Drill 
the same number of /4-inch holes through it for 
the boiler tubes and also drill, or cut out, a %-inch 
hole with its center Vie inch from the flange. 
The purpose of this hole is to form a continua- 
tion of the boiler on back to the sheet ; the throttle 
rod also passes through this hole; but it is part 
through before the back tube sheet is riveted in. 

The Crown Sheet. — Cut out the crown sheet, 
see C in Fig. 57, that is the flat horizontal sheet 
that separates the upper back part of the boiler 
from the fire-box. Cut this sheet 4% inches wide 
and 6Vs inches long and hammer over the edge 



148 The Boys' Book of Engine-Building 

shown by the dotted line all around to make a 
flange % inch wide when it will be the right size 
to fit; this is quite a particular job, because the 
corners must not be cut and they must be per- 
fectly square. 

Rivet one end of the crown sheet to the back 
tube sheet so that the upper surface of the former 
will be Hush, that is even, with the lower edge of 
the large hole in the back tube sheet. Go ahead 
now and rivet the back tube sheet to the shell of 
the boiler at a distance of 5% inches from the 
extreme back end as shown at A in Fig. 55. 
Rivet the sides of the crown sheet to the edges 
of the shell on both sides as shown in Fig. 54. 

The Boiler Tubes. — The boiler tubes, of which 
there are eight, are /4 inch in diameter and 8 
inches long. Set these in the holes in the front 
and back tube sheets and expand them and turn 
over their edges in exactly the same manner as 
in the vertical boiler described in Chapter V. 

The sheet ought to come next but for this 
little boiler it, and the front sheet of the fire-box, 
can be made in one piece so we'll take up the 
making of the fire-box next. 

The fire-box is made of four sheets riveted to- 



A Model Atlantic Type Locomotive 149 

gether. The back sheet is 5 inches wide and 
4% inches long. Scribe, that is scratch with a 
pair of compasses, a semi-circle having a radius l 
of 1 inch and another semi-circle, using the same 
center, the radius of which is i/4 inches. 

Divide the large semi-circle into 8 equal parts 
and then scribe a line from the middle of the 
semi-circle to each point which spaces it off. Cut 
out the smaller semi-circle and then cut the sheet 
through the scribed lines to the large semi-circle ; 
hammer each piece, or segment, over until the 
end of the sheet fits around the boiler. The 
whole scheme is shown at A in Fig. 58. 

Bend over each edge % inch, making the width 
of the sheet 3% inches as shown by the dotted 
line, and rivet a bar or strip of brass or iron %6 
or % inch thick, % inch wide and about 3 inches 
long across the sheet at a distance of 1% inches 
from the bottom ; this forms one of the grate bar 
rests. Now drill a hole in each segment of the 
sheet and a corresponding hole in the back lower 
end of the boiler shell and rivet them together. 

For the front of the fire-box sheet use a sheet 

1 The radius of a circle is a straight line from the center of a 
circle to its circumference; hence the radius is half the diameter 
of a circle. 



150 The Boys' Book of Engine-Building 

of copper 5 inches wide and 7% inches long, as 
shown at B in Fig. 58. Scribe a semi-circle at one 
end in the middle of the sheet the radius of which 
is 1% inches; then scribe a semi-circle whose 
radius is 2/4 inches, using the same center as 
before; cut it to shape and hammer over the 
rounded edge to form a flange % inch wide. Cut 
off each side below the middle of the semi-circle 
so that the width of the sheet is 3% inches, which 
is the width of the boiler. 

The Fittings. — Now for the fittings, that is the 
steam gauge, the water gauge, and stuffing box 
for the throttle rod. Before the pipes for these 
fittings are fixed to the front fire-box sheet rivet 
on a grate bar rest like the one on the back fire- 
box sheet, 1% inches from the bottom as shown 
by the dotted line at B, in Fig. 58. 

For the door cut out an oval hole 1 inch wide 
and 2 inches long in the sheet and V2 inch down 
from the major chord, as the straight edge of 
the semi-circle is called, and make a door % inch 
larger all round, hinge it and rivet the hinges to 
the sheet so that the door will swing over the 
opening. 

For the water gauge drill two %-inch holes 1 





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inch apart from their centers on the left hand 
side and have the lower one as close to the crown 
sheet as possible. Put a piece of threaded pipe, 
% inch long, through each hole and screw a nut 
on both ends of each pipe tight against the sheet. 

For the steam gauge drill one more %-inch hole 
in the middle near the top of the sheet and put 
in a threaded bent pipe i inch long and screw 
nuts on both sides as before. 

For the stuffing box, through which the throttle 
rod passes, drill a % 6-inch hole in the sheet V% inch 
from the middle of the rounded edge. Take a 
piece of pipe %e inch in diameter and % inch long 
and thread it the entire length; screw a nut on 
one end down % inch, slip the end of the pipe 
through the hole and screw on another nut. 
Drill a Vi 6-inch hole in a cap that will fit the pipe 
and your stuffing box is done. The position of 
all of these holes is shown at B in Fig. 58. 

Make an angle plate, to pivot the throttle lever 
to, of a strip of brass Vie inch thick, % inch wide 
and % inch long; bend over one end /4 inch and 
drill a %2-inch hole in it and a %-inch hole in the 
other end; rivet it to the fire-box sheet in a line 
with and V2 inch to the left of the stuffing box. 



A Model Atlantic Type Locomotive 153 

The throttle lever can be made of a strip of 
brass Vis inch thick, %e inch wide and 3 inches 
long; file one end to make a handle and drill a 
%-inch hole in the other end; % inch from this 
hole drill a %2-inch hole; pivot the end of the 
throttle lever to the angle plate. 

Finally, rivet the hanger for the trailing 
wheels to the firebox sheet so that the center of 
the hole through which the axle passes is exactly 
1 inch from the rim of the wheel which rests on 
the rail. 

Now slip the end of the throttle rod through 
the stuffing box and rivet the semi-circular 
flange of the front fire-box sheet to the back edge 
of the boiler shell and then rivet the back flange 
of the crown sheet to the front fire-box sheet. 

This done, bend in the front fire-box sheet at 
the line where the crown sheet is riveted to it, 
until its lower end is 1% inches from the back 
fire-box sheet; then pivot the throttle lever to 
the throttle rod. 

For the sides of the fire-box cut out two sheets 
and make the tops of each one 4% inches wide 
and the bottoms 3% inches wide and have them 
4% inches high as shown at C in Fig. 58; bend 



154 The Boys' Book of Engine-Building 

over the slanting side of each piece % inch and 
then rivet the lapped seams together. 

Now go back to the front end of the boiler and 
make the smoke-box sheet which is shown at B 
in Fig. 55. This is a copper sheet cut to the 
same size as the tube sheets but has a /4-inch 
flange. Solder or otherwise fix, a number plate 
1 inch in diameter on the center of it so that it 
will project out V2 an inch. 

Make a pair of brackets for the headlight and 
solder them to the smoke-box as shown at B in 
Fig. 55. You don't need to screw the sheet in 
the end of the smoke-box because the branched 
steam pipes have to be put in and fastened to 
the T. The headlight and the cab can be made 
after the boiler is mounted on the running gear 
and all the other finishing touches can be put 
on then. 

Making a Cardboard Model. — Here is a bit of 
advice which, if you will take it, will save you 
a lot of trouble to say nothing about material. 

Start at the beginning of this chapter and 
make a heavy cardboard tube following the di- 
mensions given in the text and in the drawings. 
Mark and cut out each separate sheet and piece, 



A Model Atlantic Type Locomotive 155 

bend them to shape and glue or paste them to- 
gether until you have the whole boiler built up 
full size. 

By making the boiler of cardboard first, you 
will see exactly where and how each seam is 
lapped and you will then have a working knowl- 
edge of how the boiler is constructed and this 
will prevent you from making a lot of mistakes 
when you come to making it up of metal. And 
now for the engine. 



CHAPTER VIII 

A MODEL ATLANTIC TYPE LOCOMOTIVE 

(Continued) 

The Parts of the Engine : The Cylinders, Steam Chests 
and Crosshead Guides ; The Engine Truck Frame ; Set- 
ting the Frame on the Truck Wheels; The Driving 
Wheels ; The Side, or Coupling Rods ; The Connecting 
Rods ; The Link Valve Gear ; The Trailing Wheels ; The 
Pilot, or Cowcatcher ; The Headlight ; The Cab ; Other 
Things to Do ; The Tender — Finishing Up the Loco- 
motive and Tender — How the Locomotive Works: How 
the Link Valve Gear Works. 

Having completed the boiler the next thing to 
do is to build the engine and the running gear. 

There is no special instruction you need to 
finish up the castings should you buy them ready- 
made but if you make the patterns and have them 
cast it is quite another matter. 

The Parts of the Engine. — The engine of a 
locomotive is really formed of two separate and 
distinct horizontal engines that set on opposite 
sides of the smoke box. 

Each engine consists of : 

(i) A cylinder and steam chest with a cross- 

156 



A Model Atlantic Type Locomotive 157 

head and crosshead block, a piston and piston 
rod, and a slide valve and valve-stem; these are 
mounted on, 

(2) The engine truck frame which, in turn, is 
fixed to the boiler by means of the saddle ; 

(3) Two pairs of driving wheels with, 

(4) Two connecting rods which connect the 
driving wheels with their respective piston rods ; 

(5) Two side rods to couple the driving 
wheels together, and 

(6) A Stephenson link valve gear for revers- 
ing the direction of the engine. 

The Cylinders, Steam Chests and Cross-head 
Guides. — The cylinders and steam chests with 
their pistons and slide valves are constructed like 
the horizontal engine described in Chapter IV, 
but the cylinders are turned around so that the 
steam chests are on top instead of on the side. 

This brings the eccentric rod out of line with 
the slide valve stem ; moreover, there are two ec- 
centrics connected to each valve rod through 
what is called a link; the purpose of this ar- 
rangement is to enable the engine driver to re- 
verse the direction of the locomotive at will. 

Further, the cross-head guide for each piston 



158 The Boys' Book of Engine-Building 



must be mounted on the end of the cylinder in- 
stead of separate from it and, finally the cylin- 




#1 



SIDE 

LOWER 
CROSS 
/7# 









iA 



Fig. 59. The Engine Truck Frame (End View) 

ders and steam chests are bolted to the sides of 
the truck frame as shown in the cross-section end 
view Fig. 59; consequently small changes must 



A Model Atlantic Type Locomotive 159 

be made in the design and construction of the 
engine and the cylinders and the steam chests 
must be made a little smaller than the horizontal 
engine previously described. 

Make each cylinder 1 inch in diameter and 
1% inches long; the steam chests should be % 




CROSS HEAD BLOCK 

Fig. 60. The Cross-head Guide and Block 

inch wide, % inch high and 1% inch long, and 
make the piston rods and slide valves to fit as 
shown at A in Fig. 60 ; the chief sizes we marked 
on the drawings. 

The crosshead guide is also shown at A in 
Fig. 60, as well as the way it is screwed to the 
cylinder head. The crosshead block that fits 



160 The Boys 9 Book of Engine-Building 

between the guides, and to which the piston rod 
is fixed and the connecting rod is pivoted as 
shown at B in Fig. 60. 

The feet on one of the cylinders and steam 
chests must be reversed before the pattern is 
cast so that they will face each other as shown 
in Fig. 59. 

The Engine Truck Frame. — After you have 
the cylinders and steam chests with their fittings 
made and in working order you can begin work 
on the engine truck, that is the part which sup- 
ports the cylinders and steam chests and on 
which the smoke-box of the boiler sets on the 
front, or truck wheels, as they are called. 

Make the truck frame first and build it up of 
sheet brass %2 or % inch thick, make two cross 
bars each 1 inch wide and 3% inches long, bend 
up each end V2 inch and drill a %2-inch hole 
through it. Drill two holes in the upper bar so 
that the saddle can be bolted to it and to the 
smoke box as shown in Fig. 59, though this is 
not done until the frame is finished. 

Drill a %-inch hole through the middle of the 
lower cross bar for the engine truck cradle as it 
is called. Make two side bars, see Figs. 59, and 



A Model Atlantic Type Locomotive 161 

61 and have them i/4 inches wide and 2 inches 
long, and drill a hole in each corner, so that you 
can bolt the cross-bars, the side bars and the 
cylinder and steam chest supports together as 
shown in Fig. 59. 

Before bolting them together cut out a sheet 
of brass Vs inch thick, 1% inches wide and 3% 
inches long and bend over one end % inch. Drill 
four %2-inch holes in this plate at one end % inch 
apart and two holes through the angle plate % 
inch apart as shown in Fig. 61. Screw or rivet 
this plate to the lower cross bar and you have the 
front frame ready for the buffer beam. 

The truck hanger, which supports the engine 
truck frame and forms the bearings for the truck 
wheels, is made of two brass bars %6 inch thick, 
% inch wide and 2V2 inches long; the bars can 
be made of a strip of brass or, better, they can be 
cast in brass. Whichever kind you use the ends 
must be set at an angle of 90 degrees to the cross 
bar to form bearings for the wheel axles. 

Drill a %-inch fcole through the end of each 
bar and two %2-inch holes, % inch from the 
middle of each bar. Screw the truck hanger side 
bars to the truck hanger cross bar and then 



162 The Boys 9 Book of Engine-Building 



pivot the lower cross bar of the frame to the 
truck hanger cross bar ; to do this make a collar, 



i 



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e 3 /6 



CROSSB/JZ 



i * 5.1 



^ 



To 



O 



FRONT 
FM/fME 




BUFFER BFAM^) 

urn 1 1 r iii ■ ■ ■ '■ u ■ ■ m—m^ 



Fig 6l. Top View of the Truck Frame 

or, as engine men call it, a truck cradle, % inch 
in diameter and % inch high and drill a Vs inch 
hole through it lengthwise. Bolt the lower cross 



A Model Atlantic Type Locomotive 163 

bar to the truck hanger cross bar with the cradle 
in between them as shown in Fig. 59. 

Setting the Frame on the Truck Wheels. — The 
standard gauge of a railroad track in the United 
States is 4 feet 8% inches but for your model loco- 
motive a track gauge of 3% 6 inches is the right 
width. The only outstanding thing to do now as 
far as the engine truck frame is concerned is to 
put on four truck, that is, front wheels. 

These wheels must be regular car wheels, that 
is flanged, as shown in Fig. 61, have a face %6 
inch wide and a diameter of 1V2 inches. Iron 
castings of car wheels of this size can be bought 
for 5 cents each and brass castings of the same 
size costs 30 cents each. 

Drill a %-inch hole through the center of each 
wheel and tap it, that is cut threads on it; cut 
off two axles of %-inch soft steel rod and make 
each one 3% inches long; thread the ends, screw 
a wheel on one end of each one with the flange 
on the inside. Next, slip the axle through the 
holes in the truck hanger bar and screw on the 
other wheel; then do the same thing with the 
other axle and wheels. 

Raise up the front end of the boiler and set 



164 The Boys' Book of Engine-Building 

it on the saddle; set the saddle on the upper 
cross bar, and this completes the engine truck 
frame. 

The Driving Wheels. — These should be 3% 
inches in diameter with a % 6-inch face and each 
one must be spoked and have a counterbalance 
weight cast on one side to balance the weight of 
the connecting rod and side rod opposite it. A 
cast iron driving wheel in the rough, but spoked 
and counterbalanced, can be bought for 25 cents 
each, while brass ones cost 50 cents each and you 
will need two pairs. Drill a %6-inch hole through 
the center of each one and thread it to fit a %- 
inch threaded axle. 

Drill and thread each wheel to fit a threaded 
%-inch crank pin opposite the counterbalance 
weight; the bearings of the connecting rods fit 
on the crank pins on the rear wheels, and the 
bearings of the side rods fit on the crank pins 
on both the front and back wheels as shown in 
Fig. 62. 

Cut off two pieces of soft steel rod Vs inch in 
diameter and % inch long and thread the ends. 
Screw one of these pins into each of the front 
wheels; cut off two more pieces of the %-inch 



A Model Atlantic Type Locomotive 165 

rod and have these 1 % inches long and threaded 
at both ends. Screw one end of each of these 
pins, which form the crank pins, into the hole 
opposite the counterbalanced weight. 

TBUCH HANGER 
SlDEB/in 



SUDZl/ALVE ROO 




TRANSMISSION BAR 



Fig. 62. Coupling and Link Gear 

The Side, or Coupling Rods. — You can either 
make patterns of and have the side rods cast, 
thereby making them look like those on a regu- 
lar locomotive, or you can make them out of a 
strip of brass Vs inch thick, %e inch wide and 
have each of them 3% inches long. 

Drill a hole in each end of each side rod Vs 
inch in diameter and exactly 2 inches apart from 
their centers and have the holes fit the crank 
pins to a nicety. 



166 The Boys' Book of Engine-Building 

The Connecting Rods, — Make two connecting 
rods in the same way that you make the side rods 
and have them of the same thickness and width, 
but 6/4 inches long; drill a hole in one end of 
each one; the other end is to be fitted with a 
joint, or fork, like the horizontal engine so that 
it can be pivoted to the cross head block with a 
pin. 

Before fitting the bearings of the rods to the 
crank pins slip a small washer over each pin in 
each one of the four driving wheels; this done, 
push the crank pins through the holes in the side 
rods, and on the ends of the crank pins on the 
front driving wheels screw on two nuts ; the in- 
side nut must not be put on too tight or the pin 
will not turn easily in the bearing of the side 
rod. The outside nut must be screwed on tightly 
to keep the inside nut from working loose, or to 
lock it as it is called. 

Slip a collar, % inch high, over each crank pin 
on each of the rear driving wheels, then put on 
the connecting rod and screw on a couple of nuts 
as before. 

Screw one end of both the front and rear axles 
to a pair of the driving wheels and push the free 



A Model Atlantic Type Locomotive ibj 

ends of the axles through the bearings on one 
side of the pedestal as shown in Fig. 63; be- 
fore screwing the driving wheels on the other 




Fig. 63. How the Driving Wheels Are Mounted 



side of the pedestal to the axles the link valve 
gear must be made. 

The Link Valve Gear. — The purpose of this 
gear is to reverse the engine. It must be made 



168 The Boys 9 Book of Engine-Building 



and the eccentrics, which are connected to it, 
must be keyed or otherwise fixed to the axle of 
the rear driving wheels before the axle is pushed 
on through the farthest bearing of the pedestal. 
The first thing to do is to know how the link 
valve gear is made. A side view of it, showing 




POTTEP CIRCtE- ~ 
SHOWS DRIYEJHHEELS 

Fig. 64. Stephenson Link Reversing Gear (Forward) 

the position of the reverse lever, link and eccen- 
trics when the gear has been set to go ahead 
is given at A in Fig. 64. The position of the re- 
verse lever and link when the engine has been 
reversed to back up is shown at B. 

Now to make the engine run smooth and even 
the pistons are set 90 degrees apart, which means 



A Model Atlantic Type Locomotive 169 

that while one piston is in one end of the cylinder 
the other piston is in the middle of its cylinder 
and this brings one of the crank pins to the ex- 
treme front or back of the wheel while the other 
crank pin is at its highest or lowest point on its 
wheel, all of which is shown in Fig. 62. 




Fig. 64. Stephenson Link Reversing Gear (Back) 

Not only this, but the eccentrics must also be 
set at 90 degrees from each other and of course 
each one of each pair — that is whichever one is 
working the slide valve — must be set 180 de- 
grees, or opposite to its respective crank pin when 
it is brought into the operating position by the 
reverse lever. 

To make the link valve gear is not so hard a 



170 The Boys' Book of Engine-Building 



job, but to set it so that the eccentrics will work 
just right will give you all the trouble you are 
looking for. 

Make four eccentrics, each of which is % inch 
in diameter and 2% inches from the center to the 
end of the rod, and drill a hole in each one for 
the axle, J4 i nc h ln diameter and %6 inch out of 
the center as shown at A in Fig. 64 ; and this will 
give a throw of }i inch. 

Next, make the links, one for each pair of ec- 
centrics; to get the proper curve the inside arc 
should be a part of a circle having a diameter of 
4% inches and each of the outer circles should be 
Vs inch larger than the next inside circle. If 
you will mark out a link the exact size and shape 
shown at A or B in Fig. 64, of the size given 
above, and saw it out of a smooth strip of wood, 
% inch thick, with a fret saw, have it cast in 
brass and then file it up, you will have a link that 
will work better than one made of sheet metal. 

The bosses, as the projections on the inside of 
the link near the ends are called, are what the 
ends of the eccentric rods are pivoted. The 
bosses in the middle of the link inside and out- 
side are what the hanger bars are fixed to. 



A Model Atlantic Type Locomotive 171 

These must project out and away from the 
curved slot in the link far enough to let the link 
block slide back and forth easily; this block is 
made in exactly the same fashion as the cross 
head block shown at B in Fig. 59. 

Now make the rocker of a strip of brass Vs 
inch thick, /4 inch wide and 2% inches long; drill 
a hole in each end and one in the middle; pivot 
one end to the link block on one side and the other 
end to the slide valve rod by a transmission bar, 
which is simply a continuation of the slide valve 
stem. The middle part of the rocker is pivoted 
to the side of the pedestal. 

This done, make the hanger of a %-inch thick 
strip of brass, %e inch wide and i/4 inches long; 
drill a hole through each end and pivot one end 
to the hanger bar but on the other side of the 
link to which the rocker is pivoted. The reverse 
shaft arm is a piece of brass Vs inch thick, % inch 
wide and 1% inches long with a hole drilled 
through both ends; it is jointed to the reach rod 
arm which is of the same size except that it is 
1^2 inches long, drill three holes in it as shown 
at A in Fig. 64 and put a pin in the lower end so 
that it can be pivoted to the pedestal. 



172 The Boys' Book of Engine-Building 

The reach rod is a long bar reaching from the 
upper end of the reverse shaft arm to the reverse 
lever in the cab. It can be made of iron or brass 
Vs inch thick, %6 inch wide and 4% inches long 
and is pivoted to the reverse lever at about the 
middle of the latter. The reverse lever should 
be 2% inches long with a latch handle and its 
lower end is pivoted to one end of a shaft % inch 
in diameter and 1 inch long, the other end of 
which is fixed to the side sheet of the fire-box. 

The latch handle works in a notched quadrant, 
the ends of which are also fixed to the side of the 
fire-box. 

Two complete sets of all these parts are needed, 
except the quadrant reverse lever and reach rod 
arm. The lower ends of both reach rod arms are 
fastened to the ends of a shaft which is held in 
place and yet free to turn in a fixed bearing. 
Now when the reverse lever is pushed ahead 
or pulled back, both link valve gears will be 
operated by it. 

When you have the two complete sets of link 
gears made, slip the eccentrics over the rear 
axle, push the latter through the bearing in the 
pedestal and screw on the other driving wheel. 



A Model Atlantic Type Locomotive 173 

This done, go ahead and couple on the other 
side rod and the other connecting rod and, finally, 
pivot the connecting rods to the crosshead block 
with a pin. 

Before making the eccentrics it is a good plan 
to make a large working model of the whole link 
gear out of thin wood and cardboard and see 
exactly how the link motion works and learn how 
it acts on the slide valve; then when you make 
the link gear out of metal you will know just 
what you are about. 

The Trailing Wheels. — These wheels are i/4 
inches in diameter and all you have to do to put 
them on is to drill a /46-inch hole in the center 
of each wheel and thread it, then make an axle 
of %-inch rod and thread it at both ends. Screw 
one end of the axle to a wheel, push the axle 
through the bearings in the hanger as shown at 
A in Fig. 55, and screw on the other wheel. 

The Pilot, or Cowcatcher. — While there are 
very few animals that are given the chance to 
horn an engine off of the track the cowcatcher 
is still the front and foremost part of a locomo- 
tive in this country. 

Make a buffer beam of wood, Vz an inch square 



174 The Boys Book of Engine-Building 

and 3^ inches long, as shown in Fig. 61, and 
screw it to the angle plate which is mounted to 
the front frame. Build up the pilot of fifteen 
wood strips and glue them to a triangular wood 
frame so that a sharp point sticks out in front 
of the buffer beam 2% inches; make it 3% inches 
high and screw it to the buffer beam. The pilot 
can be braced to the buffer beam underneath and 
it can be braced to the sides of the smoke-box 
on top. 

The Headlight. — While this can be a dummy 
cut out of wood, it is better to make it out of 
tin and solder the seams. Form a reflector of 
bright tin and put a 1 candle power tungsten 
electric lamp in front of it; run wires from it to 
the tender where you have a dry cell battery. 1 
When the lamp is lit, the beam of reflected light 
will produce a pretty and realistic effect in a 
darkened room. 

The Cab. — This can also be made of heavy 
sheet tin with the seams soldered together. Have 
it 4 inches long, 4% inches high and 5% inches 

1 Complete instructions for wiring up electric lamps will be 
found in "The Book of Electricity," by the present author and 
published by D. Appleton and Co. 



A Model Atlantic Type Locomotive 175 

wide, but let the curved roof project 2 inches, 
making the length of the cab 6 inches over all 
and put a ventilator in the top of it. 

Other Things to Do. — There are a hundred 
and one other things to do if you intend to put 
on all the attachments that are to be found on a 
real locomotive. You should by all means put 
on a hand-rail and a running board; then there 
are the springs, if you want to go to the trouble 
of making them; the air brakes, which, if you 
made the compressor right and the three-way 
cock that controls the air in the line pipe, will 
take you half as long as it did to make the en- 
gines. 

The Tender. — Every locomotive must have a 
tender to carry a supply of fuel and water. 
Make the tender of heavy sheet tin 5% inches 
wide, 3% inches high and 9 inches long. The 
body of the tender is made double all round ex- 
cept in front so that water can fill the space 
between the sides and back walls or tank and coal* 
can fill the middle and open space or bunker. 

The tender has eight wheels and all of them 
are the same size as the truck wheels of the loco- 
motive. The wheels are mounted in sets of two 



176 The Boys' Book of Engine-Building 

pairs to a frame and the body rests on the front 
and back frames. 

A pair of buffer castings is used to couple the 
tender to the locomotive and a piece of sheet 
metal which is fixed to the floor of the cab rests 
on the floor of the tender so that the fireman 
won't fall through between them when he is 
shoveling coal from the coal bin into the fire- 
box. 

Finishing Up the Locomotive and Tender. 
— Following the practice of real locomotive 
building, get a can of black enamel and paint the 
boiler from the front to the back tube sheet with 
it. 

Also paint the cab, the wheels, the head-light 
and the pilot with it to make them a shiny black. 
The steam dome, sand box, smokestack, smoke- 
box and that part of the furnace which shows 
below the cab should be painted a dull black and 
this can be done by simply adding turpentine to 
the enamel. The locomotive complete is shown 
in Fig. 64. 

How the Locomotive Works. — Of course, 
when a fire is built in the fire-box the water is 
heated as in any other type of boiler ; the hottest 



178 The Boys' Book of Engine-Building 

steam rises to the highest point which is the 
steam dome; from the dome it passes through 
the throttle stand pipe, as the bent up end of the 
main steam pipe is called, the amount going 
through depending on the steam pressure and 
the distance the throttle valve is opened. 

Having reached the T in the smoke-box, the 
steam passes out through the two branch pipes 
and thence into the steam chests where it is dis- 
tributed to the ends of the cylinders. Since 
there are two sets of steam chests and cylinders 
the power is equally divided and applied on both 
sides of the locomotive. 

Again, since the pistons are set at 90 degrees 
apart, one of the pistons is forced forward half 
way while the other one is being forced back 
half way and then both pistons travel half the 
length of their strokes in the same direction ; the 
result of these actions makes the engines run 
steadily. 

As the used steam from the cylinders exhausts 
into the smoke-box it blows out through the 
smoke-stack; this sets up a draft through the 
fire tubes and fire-box and makes the fire burn 
better. 



A Model Atlantic Type Locomotive 179 

Now since each cylinder exhausts twice during 
every revolution of the driving wheels to which 
its piston is connected and since the piston on the 
other side is set so that it is midway in its cylinder 
while the other piston is at the end of its stroke 
there are four exhausts to every revolution of 
the driving wheels, as you have probably ob- 
served not once but many times, in real loco- 
motives, especially when they are just starting. 
One thing more and that is the action of the link 
valve gear. 

How the Link Valve Gear Works. — After 
you have made the link valve gear, or even a 
model of it, you will have a clear understanding 
of the how and the why of it. 

The purpose of the link valve gear, as you 
know, is to reverse the engine and to do it the 
slide valve must be pulled or pushed over the 
inlet port of the cylinder so that the first flow 
of steam into it will force the piston in the direc- 
tion needed to make the engine go ahead. 

Suppose that the reverse lever, see Figs. 62 
and 64, is in the middle of its quadrant, the link 
is then set in such a position that the link block 
at the lower end of the rocker is in the middle of 



180 The Boys 9 Book of Engine-Building 

the link and consequently half way between the 
pair of eccentric rods which control it. 

When the link block is in this position the en- 
gine cannot work because the slide valve is 
brought to the middle of the steam chest and the 
action of the eccentric rods on it is so slight that 
it cannot move far enough in either direction to 
cover the inlet ports alternately. 

But when you throw the reverse lever forward 
as far as it will go, it will push the link down 
until the block is at the top of it and this will 
throw the slide valve to the end of the steam chest 
so that the first flow of steam will be through 
the port which will force the piston in the direc- 
tion to make the wheels revolve forward and 
thus carry the locomotive ahead. 

When the reverse lever is thrown forward the 
eccentric rod A, which is the upper one, is in a 
line with the link block and works the slide valve 
through the rocker which is pivoted to the block ; 
in this case the eccentric rod B drops down and 
though it moves to and fro it does not in any 
way affect the movement of the slide valve. 

On the other hand, when the reverse lever is 
thrown back, it pulls the link up and this brings 



A Model Atlantic Type Locomotive 181 

the eccentric rod B, which is the lower one, into 
line with the link block; when this takes place the 
eccentric rod A is raised out of the way and 
though it moves back and forth it does not in 
any way interfere with the motion of the slide 
valve set up by the eccentric rod B. 



CHAPTER IX 
STEAM, THE GIANT POWER 

The Stuff that Steam is Made of — How Water is 
Formed — What Heat Does to Water — How Water is 
Made to Boil — Getting Up Steam — About Steam Pres- 
sure — How Steam Acts — Work and Horse Power — How 
to Calculate the H. P. of Your Engine — How to Cal- 
culate the Size of a Boiler — How to Calculate the Heat- 
ing Surface of a Locomotive Boiler. 

The Stuff that Steam is Made of.— You 

know, of course, that steam is formed of water 

and you also know that water is good to drink 

and to go swimming in, but do you know just 

what the stuff is really made of? If not read 

on. Water is made up of two gases, one of 

which is hydrogen and the other is oxygen. 

Now hydrogen is the lightest substance known, 

being 14% times lighter than the air we breathe 

and 16 times lighter than the oxygen which 

keeps us alive. 

Pure hydrogen burns with a very hot flame 

and is so nearly the color of daylight it can hardly 

182 



Steam, the Giant Power 183 

be seen in it. Further, it gives off 5 times as 
much heat, when burned, as the same weight of 
coal. 

Oxygen is even a more important gas than 
hydrogen and, fortunately, there is more of it in 
nature than any other kind. It is a great gas 
to combine with other chemical substances and 
when anything burns you may know that it is 
the chemical elements in it that are combining 
with the oxygen. 

If you filled a quart measure with hydrogen 
and another quart measure with oxygen and 
weighed them, you would find that the oxygen 
weighs 16 times as much as the hydrogen. 

Chemists have found that if 1 part of hydro- 
gen by weight could be combined with 8 parts 
of oxygen, also by weight, together they would 
form water, but they also found that neither hy- 
drogen nor any other substance will combine with 
less than 16 parts of oxygen by weight. 

But it is an easy matter to combine 16 parts 
of oxygen with 2 parts of hydrogen, consequently 
you can write the formula for water thus: hy- 
drogen 2 parts to oxygen 16 parts, or you can 
use, if you like, the letters H and O that stand for 



184 The Boys' Book of Engine-Building 

hydrogen and oxygen in chemistry, or symbols 
as they are called, where H stands for 1 part of 
hydrogen and O for 16 parts of oxygen and 
then write it H 2 0. 

How Water is Formed, — To simply put 2 
parts by weight of hydrogen and 16 parts by 
weight of oxygen in a bottle and shake them up 
is not enough to make them form water ; instead 
they will remain separate gases as before, but, 
being so close together, if you light them with a 
match, or by an electric spark, they will explode 
violently and water will result. 

One way of making these gases combine chem- 
ically to form water is to pass hydrogen over a 
compound that has oxygen in it, such as copper 
oxide, and heating them. At ordinary tempera- 
tures hydrogen will not act on the copper oxide, 
but if you heat them in the flame of a Bunsen 
burner the hydrogen will combine with the oxy- 
gen to form water, and leave the copper behind. 

What Heat Does to Water.— While it is 
quite easy to produce water from hydrogen and 
oxygen, as I have just described, it is not an easy 
matter to make the rule work the other way 
about, for to change it back again into its two 



Steam, the Giant Power 185 

constituent gases, or decompose it, as it is called, 
you must raise the temperature to at least 2000 
degrees Fahrenheit. 

You can, however, easily decompose water by 
electrolysis, that is by passing a current of elec- 
tricity through it, provided you use the right kind 
of apparatus. 1 

When you ignite, that is light, an alcohol lamp 
or a Bunsen burner, or any kind of a fire, heat 
is developed and heat is a form of energy. Now 
heat is made up of little to and fro movements 
of the particles of gases that are burning or of 
the particles of matter of a substance that is 
warm or hot. 

These vibratory motions of the molecules of 
matter, as they are called, of the flame or fire 
set the particles, or molecules of matter of which 
the boiler is formed, into rapid vibration, when 
the energy of the hot molecules is soon im- 
parted to the molecules of water inside of it and 
these begin to vibrate, which warms the water 
first, then makes it hot and finally causes it to 
boil. 

How Water is Made to Boil. — Ebullition and 

1 This can be bought of the L. E. Knott Apparatus Co., Boston, 
Mass. 



1 86 The Boys 9 Book of Engine-Building 

boiling mean exactly the same thing only the first 
is the didactic, technical word and the latter is 
the simple, everyday word, so we'll use it in- 
stead. 

When water begins to boil, the first thing that 
takes place is that the air, which is always plen- 
tifully mixed with it, is forced up from the bot- 
tom in little bubbles and these rise to the top and 
pass into the air without making any noise about 
it. 

As the temperature of the water, that is the 
heat in it, is raised the molecules of water that 
rest on the bottom of the tea kettle, or the surface 
of the boiler, next to the fire, get so hot that steam 
bubbles are formed and the force of these is 
greater than the combined weight of the water 
on them and the pressure of the air above them 
can stand. 

Getting Up Steam. — When water is heated to 
212 degrees Fahrenheit it boils and no matter 
how much more heat is applied the water will 
not get any hotter. 

This curious action is due to the fact that all 
of the heat that is used to change the water into 
steam is carried off by and in the steam, and this 



Steam, the Giant Power 187 

is made to do useful work in the steam engine 
as you will presently see. 

Heat, like every other kind of energy, may be 
either kinetic, that is in motion, or potential, that 
is at rest; but wherever energy is at rest it is 
always ready to get into motion if it is given half 
a chance. 

Now when water is boiled the heat tears the 
molecules from it and from each other and 
throws them into violent motion and the more it 
is heated the greater this molecular motion be- 
comes and this is what is called the sensible heat 
of the steam. 

But not all of the kinetic energy of the heat 
is used in this way for some of it is stored up in 
the steam and this potential energy, which is 
called latent heat, charges the steam with energy 
just like electricity charges a Leyden jar. 

And don't forget that energy of motion can 
change into energy at rest, and that energy at 
rest can change into energy of motion, and, more- 
over, whether you are dealing with electricity or 
steam these changes are made forth and back 
with amazing freedom and in the twinkling of 
an eye. 



1 88 The Boys' Book of Engine-Building 

About Steam Pressure. — While steam acts 
like a gas it is called a vapor because in physics 
the word gas is used to mean a gaseous form of 
matter which can only be made into a liquid by 
applying considerable cold and pressure to it. 

On the other hand a vapor is a gaseous form 
of matter made from some liquid, or solid, sub- 
stance by heating it and which, as soon as the 
vapor cools, will condense and return to its liquid, 
or solid, state again. But steam is a gas just the 
same and it consists of the two combined gases 
that were chemically united to form water. 

Like hydrogen, or oxygen, or any other gas, 
the molecules of steam are elastic — far more elas- 
tic than solid rubber balls — and they are continu- 
ally shooting in and out in every direction. The 
speed at which a hydrogen molecule travels is 
more than a mile a second and the speed of a 
molecule of steam is very nearly as swift. 

Each and every molecule shoots in a straight 
line at the same high speed until it either hits 
another molecule, when both are stopped for an 
instant and their directions changed, or until it 
strikes the side of the vessel which holds them. 

The bombardment of the molecules on the con- 



Steam, the Giant Power 189 

taining vessel, whether it is a teapot, a boiler, or 
the cylinder of an engine, is so fast ami furious 
that the sum of all these little molecular blows 
result in a powerful force that is able to do work, 
and this is what we call steam pressure. 

The pressure of steam can be measured either 
in atmospheres or in pounds. In England both 
scales of measurement are used, but in this coun- 
try only the latter is employed. 

The word atmosphere, of course, means the 
air we breathe, but it also is used to indicate a 
pressure of 15 pounds to the square inch, since 
the weight of a column of air 1 inch square 
measured from the upper limits of the atmosphere 
to the earth at sea level is 15 pounds. A scale 
of this kind is shown at A in Fig. 66. To read 
it you have to convert the steam pressure in 
atmospheres to pressure in pounds, that is 1 at- 
mosphere means 15 pounds, 2 atmospheres 30 
pounds and so on. A scale graduated so that the 
pressure can be read directly in pounds is shown 
atB. 

How Steam Acts. — In the Boiler. — Since the 
smallest amount of steam will fill the largest 
boiler and keeping up the heat will increase the 



190 The Boys' Book of Engine-Building 

pressure of the steam you must never let the 
water in the boiler fall below a certain level or 
there will be an explosion. 




Fig. 66 A. A Steam Gauge Scale in Atmospheres 



Fig. 66 B. A Steam Gauge Scale in Pounds 

In the Engine. — When steam is admitted by 
the slide valve into the cylinder it is not only 



Steam j the Giant Power 191 

under the pressure of the steam developed by 
the sensible heat as it comes from the boiler, but 
after the steam in the cylinder is cut off by 
the slide valve its latent heat, which is energy 
at rest, begins to change into energy of motion, 
and this makes the steam keep on expanding 
and forcing the piston along. 

To make steam do as much work as possible 
it should not be allowed to exhaust until its ex- 
pansion has reduced its pressure almost to that 
of the pressure of the outside air, when it will 
escape silently ;■ but when it puffs out with a noise 
you will know that some of the energy of it is 
being wasted. 

It takes a high pressure engine to exhaust di- 
rectly into the open air, because the pressure of 
the steam in the boiler must be more than 15 
pounds to the square inch, that is, it must be 
higher than the pressure of the outside air. 
Nearly all small engines and locomotives are of 
the high pressure kind. 

It is more economical, though, to connect the 
exhaust of the engine with a vacuum chamber, 
that is, an airtight vessel in which the pressure 



192 The Boys 9 Book of Engine-Building 

of the air is less than 15 pounds to the square 
inch. 

This is done by making the steam exhaust into 
the chamber and condensing it there by admitting 
a jet of cold water; the condensed steam and 
water and any air that may have leaked into the 
chamber are then pumped out with a small pump. 

Engines fitted with vacuum chambers are 
called condensing engines and nearly all the en- 
gines of the day of Newcomen and Watt were 
of this kind. 

Work and Horse-power. — Now that you have 
seen how steam is charged with the energy of 
heat and how it has the power to do work, the 
next thing is to know how this energy can be 
measured. 

The most convenient way and the one gener- 
ally used is to simply change the heat energy into 
mechanical energy which is easier to measure. 
In the steam engine the heat energy of the steam 
acts on the piston when it is changed into me- 
chanical energy and this is in turn imparted to 
the flywheel when it is capable of doing continu- 
ous work. 

If you have ever sawed a stick of cordwood 



Steam, the Giant Power 193 

or done any other kind of labor with your hands, 
you know what work is and you also know that 
to do work takes time and effort. So if you 
wanted to measure the work you had done in 
hoeing turnips you would have to take into ac- 
count the time you had spent and the effort you 
had made. 

Now mechanical energy, or work, or power is 
measured in much the same way and that is by 
the number of pounds that a machine can raise 
a distance of one foot in one second. 

For still greater convenience a unit of work 
was introduced by James Watt; it is known as 
horse power * and is written H. P. According 
to Watt a machine which developed one horse 
power could raise 550 pounds 1 foot in 1 second 
or as it is more commonly written 

1 H.P. = 550 foot-pounds per second. 

Since there are 60 seconds in a minute and 
since nearly all measurements of this kind are in 
minutes another way of writing it is 

1 A horse power, that is work done which will lift 33,000 pounds 
1 foot high in one minute was obtained by Watt and Boulton, 
who took as their standard the strong dray horses that worked 
eight hours a day at the London breweries. 



194 The Boys' Book of Engine-Building 

i H. P. = 550 X 60 foot-pounds per minute, or 
1 H.P. = 33,000 foot-pounds per minute. 

And this is what the number means which you 
will use in the formula for calculating the horse 
power of a single cylinder engine as given below. 

How to Calculate the H.P. of Your Engine. — 
To calculate the approximate horse power of a 
single cylinder engine use this formula: 

P X L X a X 2R 



H.P.= 



33,000 

where H.P. stands for the approximate 

horse power and is what you want to find, 
P stands for the pressure of the steam on 

the piston 1 and is measured in pounds 

per square inch, 
L stands for the length of the stroke in feet, 
a stands for the area of the piston head in 

square inches and is found by multiplying 

the diameter of the piston by 3.1416, 
2 R stands for twice the observed number of 

revolutions of the flywheel 2 — this meas- 

1 This is shown roughly by the pressure gauge of the boiler. 

2 This can be found by a speed indicator, a description of which 
is given in Appendix E. 



Steam, the Giant Power 195 

urement is the same as the piston speed, 
and 
33,000 stands for the number of foot-pounds 
which equal one horse power. 

Now in your horizontal engine which has a 
1 -inch cylinder and a i%-inch stroke (or 1.75), 
suppose that P (see above) is 40 pounds to the 
square inch and that you have found R to be 300 
revolutions per minute. 

1.75 
Then: L = — .145 feet 

12 * 

a = 7r r 2 =3.1416 X .5 2 = 3.1416 X .25 = 
.7854 square inch. 
2 R = 2 X 300 = 600 revolutions per minute. 

Now substituting these values for the letters 
of the formula you have 





H.P. 






40X X 145 X 7854 X 600 






33. 


,000 




or 


H.P. 


2.733 
~ 33,ooo 




or 


H.P. 


= .08 = %2 horse 


power. 



196 The Boys' Book of Engine-Building 

How to Calculate the Size of a Boiler. — 

When I say the size of a boiler, I mean the heat- 
ing surface of a boiler necessary for a stationary 
engine of known horse power. 

The American Society of Mechanical Engi- 
neers have found by experiment that if 34.5 
pounds of water are evaporated from and at 212 
degrees Fahrenheit — that is, changed into steam, 
that 1 boiler-horse power is developed. 

Now a boiler horse power is the amount of 
power which is necessary to run an engine rated 
at 1 indicated * horse power. It has also been 
determined that in order to evaporate 34.5 
pounds of water from and at 212 F. the boiler 
must have 10 square feet of heating surface. 
That is to say, for every boiler horse power and 
likewise for every indicated horse power of the 
engine you must have 10 square feet of heating 
surface. 

Now the heating surface of a boiler is the part 
that is actually heated by the fire. This is not 
only the part that the fire strikes directly but 
the whole surface of the fire-box sheet plus two- 

1 This can be found by using a speed indicator. See Appen- 
dix E. 



Steam, the Giant Power 197 

thirds the area of the smoke-box sheet plus the 
combined area of all of the tubes. 

In the language of a formula the heating sur- 
face needed in a boiler so that it will generate 
steam to run an engine of known horse power is 

H.S. = I.H.P. X 10 
where H.S. = the heating surface and is what 

you want to find. 
I.H.P. = the indicated or known horse 
power of the engine and 
10 = the number of square feet of 
heating surface required to de- 
velop 1 boiler horse power. 

Since, now, your engine develops V12 or .08 of 
a horse power the 

H.S. = .08 X 10 or .8 of a square foot 
of heating surface to run the 
engine to its fullest power. 

To Calculate the Heating Surface of a Loco- 
motive Boiler. — The amount of heating surface 
needed for a model locomotive boiler to develop 
1 horse power, that is to evaporate 34.5 pounds 
of water from and at 212 ° F. is only 3 square 
feet. 



198 The Boys' Book of Engine-Building 

Hence to calculate the number of square feet 
of heating surface needed for a locomotive boiler 
with engines of known horse power use the fol- 
lowing formula : 

H.S. = (H.P. 1 + H.P. 2 )X3 
where H.S. = the heating surface and is what 

you want to find, 
H.P.2 = the power of the other cylinder 
and 
3 = the number of square feet of 
heating surface needed by the 
boiler to develop one boiler horse 
power. 



CHAPTER X 
A HOT AIR, OR CALORIC, ENGINE 

The Parts of the Engine: Making the Engine; The 
Expansion Cylinder, The Transfer Piston, The Piston 
Rod, The Connecting Rod, The Power Cylinder, The 
Power Piston, The Connecting Rod, The Connecting 
Pipe, The Standards, The Crank and Crankshaft, The 
Fire-box — How to Operate the Engine — How the En- 
gine Works. 

The hot air engine is the easiest of all engines 
to build; it is the simplest to make, if we except 
the steam turbine, and it is by all odds the safest 
to use. 

It is called a hot air engine because it is worked 
by the expansion and contraction of hot air — that 
is the air in the cylinders is first heated and then 
cooled and the same air is used over and over 
again. And it is truly surprising how very fast 
the temperature of the air can change. 

It is also called a caloric engine in virtue of the 
fact that the word caloric means heat ; this comes 
from the root color which is Latin for heat and 
so naturally the term caloric engine is a more 

199 



200 The Boys' Book of Engine-Building 

scientific name for that which the common people 
call a hot air engine. 

The Parts of the Engine. — There are six 
principal parts to a hot air engine; namely, (i) 
the displacement, or expansion cylinder in which 
the air is heated and cooled; (2) the displacement 
or transfer piston with its piston rod and con- 
necting rod; (3) the power cylinder where the 
working force is developed; (4) the power con- 
necting rod; (5) the crankshaft with its cranks, 
pulley and flywheel, and (6) the base which holds 
the lamp or forms the furnace for developing the 
heat. 

Making the Engine. — The Expansion Cylin- 
der. — The expansion cylinder, as shown in Fig. 
67, is the large one ; it is made of a piece of iron 
pipe with a%-inch thick wall, 2/4 inches in diam- 
eter outside measurement, and 4 inches long, and 
is threaded at both ends. 

Get two caps threaded to fit the ends of the 
pipe and drill a i-inch hole in the center of one 
of them and thread it ; this cap is for the top head 
of the cylinder. A stuffing box can be fitted to 
the head and it will make it a little more efficient 
if you want to put one on. 



A Hot Air, or Caloric, 'Engine 201 



The Transfer Piston. — Before screwing the 
head caps on the cylinder, make the transfer pis- 



<i& 




ssss^ss^^gsss^ ; 



M 




SUPPORT 



Idb 



BOTTOM CYUNOER 
HE0D 



BOTTOM HEAD 
Fig. 67. Cross-Section of Hot-Air Engine 

ton which moves in it. This can he a piece of 
pipe i/4 inches in diameter and 2% inches long. 



202 The Boys 9 Book of Engine-Building 

The reason it is made smaller than the cylinder 
will be explained presently. Thread one end of 
the pipe and screw a cap on it. 

Drill two holes, %2 inch in diameter, % inch 
from the open end and opposite each other as 
shown in the cross-section view; then turn, or 
whittle out, a hard-wood plug that will fit the 
inside of the piston pipe tightly and make it i 
inch long and drill a % 6-inch hole through the 
middle of it. 

The Piston Rod. — Make the piston rod for the 
transfer piston of brass or soft steel %e inch in 
diameter and 3% inch long, thread one end of it 
to a length of i/4 inches, file the other end flat 
and drill a %-inch hole through it. 

Screw a nut on the end of the piston down as 
far as it will go, put the threaded end through 
the hole in the piston and screw on another nut. 
You can now force the plug into the end of 
the pipe and then put in a couple of wood 
screws. 

Slip the piston rod through the hole in the 
cylinder cap and screw the caps on the cylinder 
pipe with the piston inside of it. 

The Connecting Rod. — This is the next part 



A Hot Air, or Caloric, ILngine 203 

to make. It is also made of a piece of %6-inch 
rod; have it 1 inch long with a hole drilled in one 
end for a bearing for the crank pin; drill a hole 
into the other end and thread it so that the con- 
necting fork can be screwed into it. 

Make the connecting fork of a piece of %6-inch 
rod; drill a hole through the fork for the bolt 
which is to form the pin; turn, or file, down the 
other end, thread it and screw it into the end of 
the connecting rod. The distance between the 
centers of the holes in the connecting rod is 1 
inch. 

The Power Cylinder. — This cylinder is half as 
large as the expansion cylinder and its piston 
must fit snugly and yet move easily in it. 

Use a piece of iron pipe or brass tubing — the 
latter is the best — and thread one end of it. 
Drill a %-inch hole through a cap, which is 
threaded to fit the cylinder pipe, and thread it to 
take a %6-inch pipe. 

Screw the cap on the cylinder pipe and then 
drill two %2-inch holes through one side of the 
cylinder, 1 inch apart, in a line with each other 
and thread them so that one of the standards 
which supports the crankshaft can be screwed 



204 The Boys' Book of Engine-Building 

to it. Of course the screws must not project 
through the inside of the cylinder. 

The Power Piston. — Whatever kind of metal 
you use for the power cylinder make the piston 
of the same metal so that the expansion of each 
will be about the same. 

The inside of the cylinder must be quite true 
and smooth and the piston must fit it pretty ac- 
curately, as it is not packed. Make the piston 
% inches long, cut a groove by drilling a hole % 
inch in diameter, V± inch from one of the ends; 
saw two cuts Vs inch apart through the end until 
it meets the hole and you will have a groove wide 
enough to set in the end of the connecting rod. 

Drill a %2-inch hole through the piston at right 
angles to the slot so that a pin can be driven in 
to pivot it to the connecting rod. 

The Power Connecting Rod. — There is no pis- 
ton rod used to link the piston of the power cyl- 
inder to the crank of the crankshaft, but instead 
a connecting rod only is used. 

For the connecting rod get a rod %6 inch in 
diameter and 2% inches long; hammer both ends 
flat, file them up smooth and drill a hole in each 
end with their centers 1% inches apart. Set one 



A Hot Air, or Caloric, ILngine 205 

end of the connecting rod in the groove in the 
piston and pivot them by driving in a pin. 

The Connecting Pipe. — All is now ready to 
connect the power cylinder to the expansion cyl- 
inder. The easiest way is to cut off a piece of 
% 6-inch brass pipe 1 inch long and thread both 
ends of it. 

The ends of a T, 1 as you know, are threaded 
on the inside, but in this case you want the out- 
side of the lower end of the T threaded. Screw 
the stem of the T into the hole in the head of the 
cylinder, screw a screw into one end of the T, 
screw one end of the pipe into the other end of 
the T and screw the other end of the pipe into 
the hole near the top of the expansion cylinder. 

The Standards. — The standards which sup- 
port and form the bearings for the crank, crank 
shaft and flywheel are brass bars Vs inch thick 
and % inch wide and one of them is 2% inches 
long and the other one is 3% inches long. 

Drill a %2-inch hole in one end of both stand- 
ards for the crankshaft; in the other end of the 
short standard drill two %-inch holes, 1 inch 
apart, and in the other end of the long standard 

1 See Chapter VI. 



206 The Boys' Book of Engine-Building 

drill two holes % inch apart. Screw the short 
standard to the power cylinder but don't screw 
the long standard to the top of the expansion 
cylinder just yet. 

The Crankshaft and Crank. — The crankshaft 
can be formed of a single length of bent rod or 
it can be made of two pieces of rod each of which 
is %6 inch in diameter and i% inches long, and 
thread it at both ends, 

Make two webs, as the arms for the middle 
crank are called, of Vs inch thick brass, or iron, 
strip and have each one % inch wide and % inch 
long. Drill a % 6-inch hole in one end of each 
wefy and a %-inch hole in the other end of each 
one ; thread all of them and screw a web to each 
of the shafts. 

Fix a pulley on one of the shafts and slip a 
collar fitted with a set screw over the end of each 
shaft. Now push the end of this half of the 
shaft through on a nut. 

Next, make a crank of a strip of Ys inch thick 
brass, or iron, % inch wide and % inch long; drill 
a % e-inch hole in one end and a %-inch hole in 
the other end; put it over the end of the shaft 
close up to the nut, screw on another nut and 



A Hot Air, or Caloric, Engine 207 

tighten it up so that the crank can't possibly slip 
on the shaft. 

Couple the connecting rod to the crank and 
keep them apart by means of a thick washer, or 
a collar, so that there will be enough clearance 
for the rod to pass across the end of the crank- 
shaft without danger of striking it. 

Slip a collar with a set screw in it over the 
end of the other shaft, put the latter through the 
hole in the long standard and screw the standard 
to the side of the expansion cylinder. 

Put a %-inch screw through one of the webs 
of the middle crank for the crank pin, screw on 
a nut, slip a sleeve, that is a thin piece of metal 
tubing, over the screw to form a smooth bearing 
and put the end of the connecting rod over it. 

Screw on another nut, then screw on the other 
web and finally screw a nut on the end of the 
screw good and tight so that the two shafts are 
in alignment, that is in a straight line, and so that 
the webs can't slip and a rigid crankshaft is 
formed. 

Now slip another collar with a screw in it over 
the end of the crankshaft, put the end of the long 
standard over it, screw the standard to the side 



208 The Boys' Book of Engine-Building 



of the expansion cylinder; screw the collar up 
close to it and then key, or otherwise fix to the 
end of the crankshaft a heavy 5- or 6-inch fly- 
wheel. 

The Fire-Box. — There are four parts to the 
fire-box and these are the top, the body and the 




A BUNSEN 
BURNER 

Fig. 68. A Bunsen Burner 

base and the support. The top and base can be 
cut out of heavy sheet metal and the body shaped 
up of sheet iron, but it is easier to make a cast 
iron fire-box and it is better because it is more 
rigid and as the engine sets on top of it a firm 
support is necessary. 

The top should be Vs inch thick, 5% inches in 
diameter and have a hole in it 2V2 inches in diame- 




Fig. 69. The Hot Air Engine Complete 
209 



210 The Boys' Book of Engine-Building 

ter with its center Vs inch from the true center 
of the top. The foot and the support of the en- 
gine is screwed to the top of the fire-box with the 
lower end of the expansion cylinder setting in 
the hole. 

The body can be about 4 inches in diameter 
and an inch or so higher than the Bunsen burner, 
see Fig. 68, you use to heat it. It must have a 
row of holes in the top and bottom to give the air 
a chance to circulate freely. The bottom is sim- 
ply a disk of cast iron, being /4 inch thick and 5% 
inches in diameter. The hot air engine is shown 
assembled in Fig. 69. 

To Operate the Engine. — Set a Bunsen 
burner in the base, or an alcohol lamp will work 
it in a pinch, light it and see to it that the flame 
is in the center of the bottom of the expansion 
cylinder. Give the flywheel a couple of turns to 
start it going and it will begin to develop power. 

How the Hot Air Engine Works. — To the 
end that you may know without having to rack 
your brain too hard just how a hot air engine 
works I have drawn a simple diagram of it and 
this is shown in Fig. 70. 

When the bottom of the expansion cylinder is 




EXP/lNS tQN 
CYLINDER. M 



n/?ME 



BUNStN 
BURNER 



Fig. 70. How the Hot Air Engine Works 



211 



212 The Boys' Book of Engine-Building 

heated and you start the engine off by turning 
over the flywheel the loose fitting transfer piston 
travels down and displaces, or transfers, the hot 
air in the bottom of the cylinder into the top part 
of the latter. This is easily done as there is 
plenty of room between the piston and the cylin- 
der for the air to move in. 

Not only is the hot air forced up into the top 
of the expansion cylinder, but it is also drawn 
into the power cylinder, for, while the transfer 
piston is down, the power piston is going up. But 
the moment the expanding hot air reaches the 
upper part of the cylinder and fills the power 
cylinder it cools off ; this of course makes it con- 
tract and having lost its heat energy the power 
piston is forced down by the pressure of the air 
outside on it, which is 15 pounds to the square 
inch. 

As the power piston is being forced down by 
atmospheric pressure the expansion piston is be- 
ing raised and this pushes the cooled off air in 
the top part of the expansion cylinder into the 
lower part of it when it is heated again. 

Just remember that the only purpose of the 
transfer piston is to move the air up and down 



A Hot Air, or Caloric, ^Engine 213 

in the cylinder from the hot to the cold end and 
back again. Also bear in mind that the same air 
is used over and over again. The purpose of the 
screw in the end of the T is to clean out the pipe 
connecting the cylinders should it get clogged up. 

A hot air engine is a very efficient machine for 
changing the energy of heat into mechanical mo- 
tion and it is a good one for you to build and use. 
The reason large engines of this kind are not 
used is because they must be very large when 
compared to other types of engines developing 
the same power and, besides, the heat very quickly 
burns out the bottoms of the cylinders. 

You can make a hot air engine much smaller 
than the one I have given or very considerably 
larger if you want it to do real work, providing 
you hold to about the above proportions. 



CHAPTER XI 
A y 8 -H. P. GAS ENGINE 

Gas Engines Versus Steam Engines — The Parts of a 
Gas Engine: The Cylinder — The Inlet and Exhaust 
Valves; The Exhaust Valve Mechanism; The Igniter. 
The Camshaft Bearings; The Cam and Camshaft; The 
Timing Gears ; The Piston ; The Connecting Rod ; Mak- 
ing the Crankshaft; Assembling the Crankshaft; The 
Bed of the Engine; Assembling the Engine; About Oil- 
ing the Engine ; The Flywheel and Pulley — How the Gas 
Engine Works. 

And now we come to the last of our model 
machines for converting heat into mechanical mo- 
tion and this is the gas engine. 

While the gas engine stands second to the 
steam engine as a giant power producer, it ranks 
ahead of it in modern achievement for it not only- 
made the automobile practicable but it made the 
airplane possible. 

Now a gas engine differs from a steam engine 

in that the power of the first is produced directly 

inside of the cylinder by the explosion of a gas 

while with a steam engine the power must be de- 

214 



A Ys-H. P. Gas Engine 215 

veloped, as you well know, in a separate and dis- 
tinct apparatus which we call the boiler. 

Again a gas engine is different from a steam 
engine in that in the former there is only one 
power stroke to every four movements of the pis- 
ton, the other three strokes depending on the 
momentum of a heavy flywheel where only one 
cylinder is used, while in the latter every to and 
fro movement of the piston is a power stroke. 

The third great difference between a gas en- 
gine and a steam engine is that, as you have seen, 
the explosion of gas which develops the power 
stroke is nearly instantaneous, whereas the latent 
heat in steam causes it to expand gradually and 
to develop power continuously. 

For these reasons a gas engine only reaches 
its full working power when it is running at its 
highest speed and, hence, any sudden attempt to 
use it will stall it, whereas the power of a steam 
engine can be used from the moment the throttle 
is opened and steam enters the cylinder. 

One good feature about a gas engine, though, 
is that it can be built easier and cheaper than a 
steam engine and boiler of equal power ; another 
point in its favor is that it takes up less room 



216 The Boys' Book of Engine-Building 

and weighs less for the power developed, and, 
third, it requires far less attention after it is 
started. 

The Parts of a Gas Engine. — There are five 
main parts to this gas engine and these are ( i ) 
the cylinder; (2) the piston with its connecting 
rod; (3) the crankshaft; (4) the flywheel and 
(5) the base. 

Then there are five auxiliary, or smaller, parts, 
but these are just as important as the main parts, 
in fact they are the very vitals of the engine. 
Named these parts are: (1) the inlet valve; (2) 
the exhaust valve; (3) the camshaft and cam; 
(4) the timing gears, and (5) the igniter. 

The Cylinder. — This can be made of an iron 
pipe but it must be bored out true and smooth. 
Give it an inside diameter of 1 inch, make it 2% 
inches long and thread one end of it as shown in 
Fig 71. 

Get a screw cap to fit it and drill a /4-inch hole 
through the opposite sides of the wall, drill an- 
other %-inch hole through the center of the head 
of the cap and thread all of them to fit a %6-inch 
pipe. The first two holes are for the inlet and 
the exhaust valves which let in the fresh gas and 




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217 



21 8 The Boys' Book of Engine-Building 

let out the burned gases. The hole in the head 
of the cap is for the igniter. 

Drill a %-inch hole % inch back from the front 
end of the cylinder and through the wall and 
thread it for an oil cup. These can be bought 
ready made with screw tops for 25 cents each. 

The Inlet and Exhaust Valves. — A simple way 
to make both the inlet and the exhaust valves, 
if you haven't a lathe, is to take a /46-inch elbow 
for each one (see Chapter VI). 

Thread one of the ends on the outside and then 
ream it out to form a beveled edge as shown in 
Figs. 71 and 72, to form a seat, as it is called. 
Drill a Vi 6-inch hole through the elbow for 
the valve stem so that it will be exactly in the 
center of the end of the elbow that is beveled 
out. 

Make a valve head of a disk of soft steel Viq 
inch thick and % inch in diameter and bevel the 
rim so that it will fit accurately in the beveled 
end of the elbow. Drill a /46-inch hole through 
the center of it and thread it. For the valve 
stem use a soft steel rod He inch in diameter and 
1% inch long and thread both ends of it, screw 
one end into the valve head as shown at A in Fig. 



A Vs-H. P. Gas Engine 



219 



71 and slip the other end through the hole in the 
elbow. 



^ 



-*■ — rr 
I * 




Fig. 72. Cross-Section View of Cylinder Showing Exhaust 

Mechanism 

Next make an open spiral spring of very thin 
brass wire Vis inch in diameter. Put this on over 
the valve stem with one of its ends resting against 



220 The Boys' Book of Engine-Building 

the elbow, slip on a washer and then screw two 
nuts on the end of the stem. The purpose of the 
spring is to make the valve head seat properly. 

The inlet valve is the lower one and no mech- 
anism is needed to work it, for when the suction 
stroke takes place, that is, the stroke of the piston 
which pulls the explosive mixture of air and gas 
into the cvlinder the suction is sufficient in itself 
to lift the valve out of its seat. 

The Exhaust Valve Mechanism. — The elbow, 
valve and valve stem of the exhaust valve are 
made exactly like the inlet valve, but it must be 
mechanically opened against the pressure of the 
spring to let out the burnt gases. 

A picture of this device to open the valve is 
shown in the cross section view Fig. J2 and in 
the top view of the engine in Fig. J2, while all 
the parts drawn out in perspective are shown 
at A, B, C and D in Fig. 73. It is easier to make 
a pattern for the support B and the rocker arm 
D and have them cast in brass than to shape 
them up by hand. 

The support is formed of a standard 1 % inches 
high at the back and 1% inches high in front; 
half of the top end is cut away as shown at B 



A Vs-H. P. Gas Engine 



221 



and a hole is drilled through the remaining part. 
The standard rests on a base curved to fit the 
cylinder and you must drill a hole in each end 
for the screws. Projecting out in front of the 



VALVE 
HEAD 







? ARM 



%2> 




Fig. 73. Parts of the Exhaust Valve Mechanism 

standard is an arm with a hole in the end just 
large enough to let the valve rod, see C in Fig. 73, 
slip through it. 

The rocker arm D is Vie inch thick, except 
near the middle where it bulges out to Vie inch; 



222 The Boys' Book of Engine-Building 



it is % inch wide and i%6 inch long and a slot 
Viq inch wide and % inch long is sawed out of 
one end. 

Half of the bulged part is cut away and a hole 
is drilled through the part that is left. A %-inch 
hole is drilled in the other end and the distance 
between the centers of these holes is %6 of an 
iEEll 




® 



Fig. 74. Top View of the Engine 

inch. The rocker arm is now pivoted to the 
standard and, since both are cut out half way, 
the hole in the end of the rocker arm and the 
hole in the end of the arm of the support will be 
directly over and in a line with each other. 

The cam rod is a steel rod Vs inch in diameter 
and 2% inches long and threaded on one end; 



A Vs-H. P. Gas Engine 223 

screw on two nuts, slip the end of the rod through 
the hole in the arm of the standard and the end 
with the nuts on it through the hole in the rocker 
arm; then screw on two more nuts as shown in 
the cross section view, Fig. J2. 

When you have assembled the parts, screw the 
base of the support to the cylinder so that one end 
of the base, which should be rounded out, sets 
against the elbow as is also shown in Fig. J2, 
when the slotted end of the rocker arm will set 
over the end of the valve stem. 

The Igniter. — There are two ways to fire the 
fuel mixture of a small internal combustion en- 
gine: (1) by a hot metal tube and (2) by an 
electric spark. 1 As the hot tube igniter is the 
simplest to make, as well as to use, I prefer it for 
this little engine. 

The whole igniter must be made of iron, except 
the hot tube which is of steel and the mica wash- 
ers and rings which insulate the tube when hot 
from the shell of the igniter to keep it from los- 
ing too much of its heat. 

1 For a very full description of how electric spark ignition 
works, see "Keeping up with Your Motor Car," by the author, 
and published by D. Appleton and Co., New York. 



224 The Boys' Book of Engine-Building 

Get a piece of pipe i /4 inches outside diameter 
and iVs inches long and thread both ends of it; 
drill a % 6-inch hole through the wall half way 
between the ends and thread it to fit a /4-inch 
pipe. Fit two caps to the ends of the large pipe 
and drill a /4-inch hole in the center of one of 
them and also drill four screw holes around the 
hole in the center so that the cap can be screwed 
to the head of the cylinder, as shown in Fig. 75. 
Drill a %2-inch hole in the center of the other cap, 
thread it and put in a screw with a nut on it. 
Next get a large iron washer, %6 inch thick, that 
will fit inside the iron tube snugly and it must 
have a /4-inch hole in it; also get a small iron 
disk Yie inch thick and V2 an inch in diameter. 

For the ignition tube use a piece of steel tube 
%6 inch in diameter and 1 inch long and, last of 
all, get a mica * washer, or use enough of them to 
make a washer Vis inch thick; two mica rings to 
fit over the steel tube — these are shown by the 
black parts in Fig. 75 — and a mica disk each of 
which is Yie inch thick and V2 inch in diameter. 

1 Mica can be bought in hardware stores. Mica in every shape 
and form is sold by Eugene Munsell and Co., 68 Church Street, 
New York City. 



A Vs-H. P. Gas Engine 



225 



To assemble the igniter screw the cap with the 
large hole in it to the head of the cylinder ; next 
screw in the iron pipe; set the mica washer 



w 

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4__^?o/v /ROM 




UBE W/fSHER 
WRING 

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TUBE TO GAS 



Fig. 75. Cross Section View of the Igniter 

against the head of the cylinder; slip the mica 
ring over one end of the steel tube and set the 
tube up against the washer. 



226 The Boys' Book of Engine-Building 

Slip a mica ring on the other end of the steel 
tube and fit the iron washer over the mica ring 
and inside the pipe; set the mica disk against the 
end of the tube and inside of the iron washer; 
also set the thin iron disk against the mica disk 
inside of the washer and then screw on the re- 
maining cap. 

Finally, tighten up the screw in the cap to make 
the steel tube gas-tight around the ends. This 
completes the igniter except for the Bunsen 
burner which is used to heat the steel ignition 
tube. It is called a Bunsen burner because it 
was invented by Bunsen, a great German sci- 
entist who lived in the 19th century. 

It is formed of a tube the lower end of which 
is connected to a supply of gas and the upper end 
is left open ; holes are drilled in the pipe near the 
lower end and, when the gas is lit at the upper 
end, air is drawn into the pipe where it mixes 
with the gas and this makes a hot flame. 

All you have to do to make a Bunsen burner 
for the igniter is to get a /4-inch iron pipe 2V2 
inches long, thread one end of it and bend the 
other end over about 1 inch; drill a %-inch hole 
clear through the pipe just above the bend and 



A V&'H. P. Gas Engine 



227 



fit a tin, or a brass, ring % inch high and which 
also has a pair of holes drilled in it, over the 
pipe where the air holes are. By turning the 
ring around, the air holes are opened or closed 
and hence the amount of air can be regulated. 

Screw the Bunsen burner pipe into the iron 
pipe of the igniter and all of your fine work on the 
engine is done. 




CAM 



LUG- 



THE CAM THE B Em f NO 

Fig. 76. The Cam and Camshaft Bearing 

The Camshaft Bearings. — Make two patterns 
as shown at A in Fig. 76 for the bearings for 
the camshaft and have the base of one % inch 
thick and the base of the other % inch thick ; the 
reason one must be made thicker than the other 
is because one is screwed to the front end of 
the cylinder which is smaller all around by Vs 



228 The Boys' Book of Engine-Building 

inch than the cap to which the other bearing is 
screwed. The base of each bearing is % inch 
long and each must be curved to fit the cylinder. 

Glue a lug on the rounded side of each base V± 
inch thick, Yie inch wide and %e inch long and 
drill a % 6-inch hole through the end. After the 
patterns are cast, screw the one with the thinnest 
base to the extreme end of the cap on the cylinder 
and screw the other bearing to the front end of 
the cylinder as shown in the top view Fig. 74 
and in the perspective drawing Fig. 79, be sure 
to have the holes in a straight line with each 
other. 

The Cam and Camshaft. — To raise the cam 
rod up so that the rocker arm will push the valve 
stem down and thus open the exhaust valve when 
the exhaust stroke takes place, a cam is used and 
this is driven from the crankshaft by means of a 
camshaft and a pair of timing gears as shown 
in the top view, Fig. 74, and in the perspective 
drawing, Fig. 79. 

The cam is an elliptic-shaped piece of steel with 
a hole through the large end as shown at B in 
Fig. 76, and its purpose is to raise the cam rod 
every time it turns around once, which it does 



A Vs-H. P. Gas Engine 229 

since the lower end of the rod rests on it. It is 
screwed, keyed or otherwise fixed, on one end of 
the camshaft. 

The camshaft is a steel rod %e inch in diameter 
and 5% inches long. Slip the free end through 
the bearing on the cap of the cylinder, put a collar 
on it and then push it on through the bearing on 
the front end of the cylinder and screw up the 
collar so that the shaft can't slide in its bearings. 
A timing gear is fixed to the free end of the shaft. 

The Timing Gears. — Now since there is only 
one explosion to every four strokes of the piston 
it must be clear that there is only need for the 
exhaust valve to open once in this number of 
strokes to get rid of the burnt gases. 

To do this the camshaft must make only one 
revolution while the crankshaft makes two com- 
plete turns. To get this result a pair of beveled 
gears is used and the gear on the camshaft must 
have twice as many teeth cut on it as the one on 
the crankshaft which drives it. 

A pair of beveled gears, one of which is % inch 
in diameter and has 1 5 teeth and the other 1 inch 
in diameter and with 30 teeth, is well suited to 
this engine. Bevel gears of these sizes can be 



230 The Boys 9 Book of Engine-Building 

bought of dealers in model supplies for about 75 
cents per pair. The large bevel gear is, of course, 
fixed to the end of the camshaft and the small 
gear is keyed to the crankshaft as shown in Fig. 

74. 

The Piston. — Having all these small but highly 
important details attended to, you can now go 
ahead with the heavier parts of the engine. 

The piston should be made of iron and care- 
fully fitted to the inside of the cylinder ; it is 1 inch 
in diameter and 1% inches long. Make it of a 
piece of iron pipe i%6 inches long and it ought 
to be turned down to make a good fit ; thread the 
inside of one end and bevel the inside of the other 
end to allow room for the connecting rod. Make 
a screw plug Vie inch thick and thread it to fit the 
pipe and then round off the end as shown in Fig. 

7i. 

Drill a % 6-inch hole through the piston wall, 

V2 an inch from the open end for the wrist pin, or 

gudgeon pin as the pin that couples the connecting 

rod to the piston is more properly called. How 

the connecting rod is fitted to it will be told below. 

The Connecting Rod. — Make the connecting 

rod of brass /4 inch thick, %e inch wide on one 



A Vs-H. P. Gas Engine 231 

end and taper it down to % inch wide on the other 
end; let it be 3% inches long and round off both 
ends as is also shown in Fig. 71. 

In the small end drill a % 6-inch hole for the 
wrist pin and in the large end drill a %-inch hole 
for the pin of the crankshaft to go through. You 
can make the connecting rod in two ways and 
these are (1) by having it cast in brass and (2) 
by shaping it out of a brass bar. 

If you have it cast, make the pattern with 
bosses on the ends, that is projecting disks; but if 
you shape it out of a brass bar make two collars 
Vie inch in diameter and % inch long; drill a %6- 
inch hole through each one and round it off so 
that it fits the curve of the inside of the piston. 

Get a piece of steel rod %6 inch in diameter, 
1 inch long, for the wrist pin. Now push the 
end of the pin through the wall of the piston, on 
through a collar, next through the small end of 
the connecting rod, then on through the other 
collar and, finally, through the wall of the piston. 
There is no need to fasten the wrist pin in tight 
because, when the piston is in the cylinder, it is 
there to stay. 

Making the Crankshaft. — This can be forged 



232 The Boys' Book of Engine-Building 

of a single length of steel rod but it will be easier 
for you to make it of three pieces of steel and 
connect them together with brass, or steel, webs. 
To make a crankshaft after the latter fashion 
get a piece of /4-inch steel rod 1% inches long 
for the crank pin and two more pieces of the 
same diameter and each of which are 2% inches 




Fig. 77. The Crank Web 



long for the shaft. Thread both ends of all the 
pieces and fit them with nuts. 

Cut off two pieces of brass bar each of which 
is Vs inch thick, V2 an inch wide and i%e inches 
long for the webs and drill a % 6-inch hole in one 
end of each web and thread it to fit the shaft. 
Drill a /4-inch hole in the other end of the web 



A Vs-H. P. Gas Engine 233 

and have the centers of the holes exactly % inch 
apart as shown in Fig. yy. 

Assembling the Crankshaft. — The crankshaft 
can be completely assembled and the connecting 
rod coupled to it before it is mounted in the jour- 
nal-bearing as the latter is halved, that is cut in 
two as shown in Fig. 71. 

To assemble the crankshaft you will need ten 
nuts, three washers, %2 inch thick, and three col- 
lars, %6 inch thick; the washers and the collars 
must fit snugly over the shafts and all of them 
should be V2 inch in diameter. 

Begin by screwing, or otherwise fixing, the 
small bevel gear to one of the shafts % inch down 
from the end, see Fig. 74, now screw on a nut, 
next screw on the web and, lastly, screw on an- 
other nut. On the other shaft screw a nut %e 
inch down on one end, screw on the web, then 
screw on another nut and slip on a collar. The 
webs must be put on tight or they will twist 
around on the shafts. 

Slip the end of the connecting rod over the 
crank pin, put a collar on each side of it, screw 
the ends of the webs down on the pin and screw 
two nuts on each end of it. This construction 



234 The Boys' Book of Engine-Building 

Secures the crank pin to the shafts so that a 
fairly rigid unit is made of it, while the bearing 
of the connecting rod can turn freely. 

The Bed of the Engine. — The bed for this en- 




Fig. 78. Back End View of The Gas Engine 



gine ought, by all means, to be a cast one. To 
make a pattern for the bed measure up the side, 
top and end elevations shown in Figs. 71, 74 and 
78 and then by looking at the picture of the com- 



A Vs-H. P. Gas Engine 235 

pleted engine in Fig. 79 you will see precisely 
how it is put together. 

If you have the bed cast in iron the journal 
boxes should be fitted with Babbitt metal bear- 
ings 1 for the friction of steel sliding on iron 
or brass is much greater than steel on Babbitt 
metal. 

Assembling the Engine. — Drill four %-inch 
holes in the cradle of the bed, that is the concave 
part on which the cylinder rests; drill four cor- 
responding holes through the wall of the cylinder 
near the open end and screw the bed to the cylin- 
der. 

Put the piston in the cylinder and set the crank- 
shaft in the bearings of the bed when the small 
timing gear on the crankshaft will mesh with 
the large timing gear on the camshaft as shown 
in Fig. 74 and this will bring the collar on the 
other end of the camshaft up against the journal 
box. 

When you have the connecting rod, the timing 
gears and the crankshaft adjusted so that they 
all run smoothly, screw on the tops of the journal 
boxes. Slip a washer on each end of the crank- 

1 See Appendix. 



236 The Boys' Book of Engine-Building 

shaft outside of the journal boxes and screw a 
nut on the end of the shaft that carries the bevel 
gear. 

The Flywheel and Pulley. — The flywheel should 
be a heavy one with at least a %-inch face and it 
should be 5 inches in diameter. A spoked wheel 
of this size can be bought ready to use. 

It is a good scheme to fit a handle to one of 
the spokes to crank the engine with when starting 
it. Fix the flywheel on the end of the crank- 
shaft outside of the journal box and slip on a 
washer. 

The pulley can have a flat face % inch wide 
and a diameter of about 1 inch ; fix it to the shaft 
next to the washer and screw on a nut all of 
which is shown in Fig. 74. 

About Oiling the Engine. — One of the chief 
things to do to make an engine run and to keep 
it running is to supply all the working parts 
plentifully with oil. 

The piston should be well lubricated with a 
good grade of light automobile engine oil and 
this can be done by remembering to keep the oil 
cup filled with oil all the time. 

It is a good scheme to fit an oil cup in the end 




237 



238 The Boys' Book of Engine-Building 



of the connecting rod and also in each bearing 
of the crankshaft and don't forget to oil up all 
the other little parts often. 

How the Gas Engine Works. — The way a 
single cylinder gas engine works can be easily 
understood by looking at the diagrams shown in 
Fig. 80. 



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How the Gas Engine Works 




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The diagrams A, B, C and D show the same 
cylinder during four strokes of the piston or 
cycles as they are called, and, hence, during two 
complete revolutions of the crankshaft. 

The diagram A shows the piston making its 
suction stroke and this lifts the inlet valve out 
of its seat and draws in the mixed air and gas, 
or fuel mixture. While this operation is taking 



A Vs-H. P. Gas Engine 239 

place the exhaust valve is kept closed by its 
spring. 

When the piston has reached the end of its 
suction stroke and begins to move back it com- 
presses the fuel mixture, or charge as it is now 
called, and this in consequence is named the com- 
pression stroke. Of course the inlet and the ex- 
haust valves are closed while the compression 
stroke is being made, not only by their respective 
springs but because the pressure of the gas is on 
them. 

The fuel charge is not fired by the hot tube of 
the igniter until the gas is compressed for the 
reason that it is not hot enough ; but when a gas 
is compressed it develops heat and this, added 
to the heat of the hot tube, raises the tempera- 
ture high enough to explode the gas. 

The instant the gas is fired it explodes and 
the force of it drives the piston out and so makes 
the power stroke. Naturally the force of the ex- 
plosion acting on the valves would hold them in 
their seats even if the springs did not keep them 
closed. 

Now, while the piston was making these three 
strokes the camshaft made only three-quarters of 



240 The Boys' Book of Engine-Building 

a revolution but at the end of the power stroke 
the cam on the camshaft reached a position where 
it began to lift the exhaust valve rod and this in 
turn opened the exhaust valve ; then as the piston 
moved back it forced the waste gases out of the 
cylinder through the exhaust port. 

From what has been said above it will be seen 
that there are four separate operations per- 
formed by the piston and for this reason a gas 
engine of this kind is called a four cycle engine ; 
it is also called an Otto cycle gas engine from 
Otto, a German engineer who invented it. 

Since there is only one power stroke to every 
two revolutions of the crankshaft, a heavy fly- 
wheel must be used to carry the crankshaft around 
during the other three strokes. In automobiles, 
motor boats, motor cycles and airplanes four or 
more cylinders are used and the pistons of all of 
them are connected to one crankshaft in such a 
way that the power strokes are practically con- 
tinuous and so that a very small flywheel can be 
used. 



CHAPTER XII 
USEFUL INFORMATION 

More About Pattern Making — Alloys and their prop- 
erties: Red Brass; Standard Brass; Pewter; Fusible 
Alloy; Mitis Metal — Properties of some Useful Metals: 
Cast Iron; Soft Steel; Copper; Brass. 

About Pattern Making. — In Chapter IV I 
told you a little about making patterns but there 
are some other things you should know in order 
to get good castings from them. 

Pattern making is a very particular job and, 
if the pattern is at all complicated, it requires a 
good deal of knowing how in order to make the 
casting draw from the mold. The main thing in 
making simple patterns is to have the joints neat 
and close fitting. 

If you should glue parts of the pattern to- 
gether or get any grease on it, clean it off well 
before shellacking or the sand will stick to it and 
a poor casting will result. As I mentioned in 
Chapter IV the pattern must taper off slightly to 

permit it to be easily drawn from the sand. 

241 



242 The Boys 9 Book of Engine -Building 

In allowing for the shrinkage of the metal the 
casting is made of when it cools off the size of 
it must be taken into consideration. As iron 
shrinks Yio inch in a foot, brass % inch in a foot 
and steel and aluminum about % inch in a foot 
you can make your patterns accordingly. 1 

If the castings are to be left rough, they do not 
need to be made as large as when they are to be 
finished up either by hand or in a machine. For 
iron castings an allowance of % inch to the foot 
is usually made for the outside parts to be ma- 
chined and %6 inch for the inside parts, while 
for brass castings Yi§ inch for the outside and 
Vs for the inside surfaces is enough for fair sized 
castings. 

If a casting is to have a hole in it, as for in- 
stance, a cylinder, the pattern can be made solid 
and a print, that is a wooden plug the size and 
shape of the hole to be made is fixed to the ends 
where the hole is to be formed. 

These prints must be marked as such when 
you send the pattern to the foundry so that the 

1 You can buy a shrinkage rule for $1.50 of Hammacher, 
Schlemmer and Co., Fourth Ave. and 13th Street, New York 
City. A shrinkage rule is graduated to allow for the shrinkage 
of different metals. 



Useful Information 243 

moulder will know they are intended for a hole 
and not solid ends. 

Alloys and Their Properties. — An alloy is a 
metal made by melting two or more metals and 
mixing them together. Alloys take on proper- 
ties that are entirely different from the metals 
they are made of. 

Gun Metal. — This alloy has a very fine grain; 
it is yellow gray in color and in time past was 
used for gun castings. It is sometimes used now 
for high speed bearings and it makes very pretty 
model engine castings. It is composed of 

90 per cent, of copper and 
10 per cent, of tin. 

Red Brass. — This alloy is very tough and is 
largely used for engine work. It is made of 

90 per cent, of copper and 
10 per cent, of zinc. 

Standard Brass. — This is a brass alloy that 
makes good castings and works well. It is 
formed of 

66.6 per cent, of copper and 
33.3 per cent, of zinc. 



244 The Boys' Book of Engine-Building 

Pewter. — This old-time alloy was formerly 
used for making plates, tea sets, etc. It is easy 
to work, is fairly hard and has a low melting 
point. It is composed of 

80 per cent, of tin and 
20 per cent, of lead. 

Fusible Alloy. — It is also called Rose's metal 
because it was discovered by Valentine Rose; it 
dates back to 1772. It melts below the boiling 
point of water. It is formed of 

50 per cent, of bismuth 
25 per cent, of tin and 
25 per cent, of lead. 

Mitts Metal. — This alloy melts and flows 
easily, has all the properties of the best forged 
iron and makes good castings. It is made of 
Swedish iron with /4oo to /4ooo part by weight 
of aluminum. 

Properties of Some Useful Metals. — Cast 
Iron. — There are two kinds of cast iron and 
these are, (1) white and (2) gray. You can 
easily tell them apart for white cast iron is 
smooth and white, while gray cast iron has a 



Useful Information 245 

grayish rough surface. Always have your cast- 
ings made of gray cast iron because it is much 
softer and easier to work than white cast iron. 

Soft Steel. — The best kind of mild, or soft 
steel has a sort of a fine bluish white color. The 
kind that is generally used for making machine 
parts is cold rolled bright Bessemer steel, but 
there are softer grades on the market. 

Bessemer steel is easy working and can be 
filed, drilled, turned and threaded; in working it 
always use plenty of machine oil on it. It can 
also be bent cold and makes good f orgings. 

Copper. — Copper of good grade has a smooth, 
fine-grained surface, while the poorer grades are 
usually pitted and rough. 

It is exceedingly malleable, which means that 
it can be hammered or rolled without breaking 
or cracking, and ductile, that is it can be drawn 
out into wire. It can also be forged at a low 
red heat, but it must not be heated anywhere 
near its melting point or it becomes very 
brittle. 

Copper is not an easy metal to drill, file or turn, 
but it is easier worked if turpentine or soapy 
water is used to lubricate it. Its toughness and 



246 The Boys 9 Book of Engine-Building 

malleability makes it a very serviceable metal for 
model boilers. 

Brass. — This alloy is quite malleable and duc- 
tile and makes very fine castings. You can saw, 
turn, file, thread and solder it easily and you do 
not need to lubricate it when performing these 
operations. 



APPENDICES 

APPENDIX A 

Fluxes. — If metals which are to be soldered together 
are not clean the solder will not stick. To clean metals 
for soldering a flux must be used and fluxes of differ- 
ent kinds are needed for different metals. 

Muriatic Acid Solution. — Muriatic acid, or hydro- 
chloric acid to give it its right name, mixed with twice 
its quantity of water and in which zinc clippings are 
dissolved makes a soldering fluid that will solder tin, 
brass, copper, iron and steel, and nearly all other metals 
except aluminum. 

When used on iron and steel wash it off very clean 
and dry well or it will rust the work. You can make this 
soldering fluid by buying 5 cents' worth of zinc chloride 
which you can get at any drug store, with an equal quan- 
tity of water. 

Sal Ammoniac. — These salts are a good flux for sol- 
dering copper. 

Tallow, Venice Turpentine and Gallipoli Oil. — All of 
these are useful as fluxes for soldering lead and pewter 
and nearly all metals that melt at a low temperature. 

Resin. — Strictly speaking this is not a flux since it 
does not clean off the grease and oxides but for solder- 
ing new tinware it can't be beat though you must scrape 
the tin clean first. 

APPENDIX B 

Model Engine Castings. — Horizontal Steam Engine. — 
Complete sets of castings for a horizontal engine can be 
bought in brass and iron as follows: 

247 



248 



Appendices 



(0) A horizontal engine with a %-irich bore and a 2- 
inch stroke, all brass, for $4.00. 

(1) Ditto with a i%-inch bore and a 3-inch stroke, 
all iron, for $4.00, or all brass for $10.00, and 

(3) Ditto with a 2-inch bore and a 4-inch stroke, all 
iron for $10.00. 



K 



Els 






w 

Fig. 81. A Cylinder and Piston Ready to Work 

Parts for the Above Engines. — If you want to buy 
some of the parts finished and ready to work these can 
be had in iron and at the following prices : 

No. o No. 1 No. 2 
Parts of Engine. Engine. Engine. Engine. 

Cylinder and steam chest finished 

and in working order, as shown in 

Fig. 79 $10.00 $15.00 $20.00 

Crankshaft and crank 2.50 3.50 5.00 

Bearings for the shaft 2.00 2.50 3.50 

Wrought iron connecting rod 1.50 3.50 5.00 

Eccentric and straps 2.50 3.50 5.00 

Flywheel, bored and faced 2.00 3.00 4.00 

Castings of Cylinders. — Or you can get the castings 
for the cylinders in the rough and finish them yourself ; 
they cost : 

Diameter of Cylinder... 1 inch 1% inch 2 inch 
Price, bored $1.50 $2.00 $4.00 

The i%- and 2-inch cylinders have the ports cast in 
them while the small cylinder which is made of brass 
must have the ports drilled in it and an extra charge of 
75 cents is made for doing it. 



Appendices 249 

Castings for an Oscillating Engine. — A complete set 
of castings for making an oscillating cylinder engine of 
fairly decent size can be bought of model works at these 
prices : 

No. o Engine with J^-inch bore and i^-inch stroke $i-75 

No. 1 Engine with i -inch bore and 2 -inch stroke 2.50 

No. 2 Engine with i^-inch bore and 3 -inch stroke 3.00 

When these engines are finished ready to run the No. 
o sells for $15.00; the No. 1, for $20.00, and the No. 2 
for $30.00. The engine is shown in Fig. 80. 




Fig. 82. An Oscillating Cylinder Engine 

Castings for the Corliss Type of Engine. — An up-to- 
date horizontal engine of the Corliss type as shown in 
Fig. 81 is built just like a large engine, the design, con- 
struction and material being the same in every particu- 
lar. The cylinder has a i%-inch bore and a 2-inch 
stroke. Makers furnish them in three ways or classes 
as they call them, to wit : 

Class A. — A complete set of castings, with all the ports 
cored in, including piston rod and valve stem. Price 

$4.50. 



250 



Appendices 



Class B. — Same as above with cylinder bored and 
faced, valves and steam chest seat planed and slide 
dressed. $5.50. 

Class C. — Besides the above the balance wheel is 
bored, turned and polished, the stuffing boxes are fitted 
on and the eccentric is bored and turned. Price $6.50. 

A finished engine of this kind costs $25.00. 

Castings for a Half-Horse Power Corliss Engine. — 
This engine is made like the foregoing Corliss model, 




Fig. 83. A Model Corliss Engine 

but has a i%-inch bore cylinder and a 3-inch stroke, 
while the flywheel has a 2-inch face and is 10 inches in 
diameter. 

The complete set of castings with the cylinder bored, 
steam chest and valve seat planed, crank shaft, piston 
and valve rods turned, $15.00, or you can buy the en- 
gine complete all ready to run for $50.00. 



APPENDIX C 

Steam Boilers for Model Engines. — Vertical Tube 
Boilers.— A vertical tube boiler large enough to run ^n 



Appendices 2£l 

engine of 1%-inch bore and a 3-inch stroke with all the 
fittings can be bought for about $30.00 and a size large 
enough for running a half horse power boiler for $50.00. 

The smaller size boiler is 10 inches in diameter and 
16 inches high and has 20 brass tubes % inch in diame- 
ter and 10% inches long. The shell is made of %-inch 
wrought iron with lap welded seams, while the smoke- 
box and fire-box are of cast iron. The outside casting 
and smoke-stack are made of Russia iron. 

The boiler is tested at 160 pounds cold water pressure 
and it is safe to run it at a steam pressure of 75 to 100 
pounds. 

Dimensions of Small Steam Boilers. — 

Mate- Water Shp'g 

Boiler Largest No. rial Pounds Line Weight 

Horse Base Total Fire- of of Tested from in 

Power Diameter Height Box Tubes Tubes at Floor Pounds 

54 10-inch 21 5x7 20 Brass 250 14 90 

' Yz 16 31 6 x g)/ 2 32 Brass 250 22 25o 

V/2 21 41 9x13 51 Steel 200 27 425 

These boilers are made to burn gas, gasoline, kerosene, 
hard coal, charcoal, alcohol or wood. If you are in- 
terested in a boiler of this kind write to the Lipp Elec- 
tric and Machine Co., Paterson, N. J. 



APPENDIX D 

Other Castings for Engines and Boilers. — Governors. 
— A set of brass castings for a small governor can be pur- 
chased for 60 cents and a larger size for $1.00. 

Force Pumps. — Three sizes of castings for force 
pumps are obtainable and these are 

No. 1 — ^4-inch bore and i^-inch stroke $ .50 

No. 2 — ^-inch bore and 3 -inch stroke 75 

No. 3 — ^-inch bore and 4 -inch stroke 1.00 

The No. 1 force pump, finished, costs .3.50 



2£2 Appendices 

The No. 2 force pump, finished, costs $4.50 

The No. 3 force pump, finished, costs 5.50 

Safety Valves, — The castings for a small safety valve 
with a %-i nc h steam passage and a 5-inch lever costs 
25 cents while a j^-inch safety valve with a ^-inch steam 
passage and a 6-inch lever sells for 35 cents. 

Note. — The prices listed ahove are those quoted by the manu- 
facturers at the time this book was written. Since these are 
war-times the prices are subject to change but I here give them 
so that you can at least judge the relative value of the different 
parts. 

Where to Buy Engine Fittings. — Write for catalogues 
and price-lists to Arthur H. Wightman, 132 Milk Street, 
Boston, Mass. ; The Chicago Model Works, Madison 
Street, Chicago, 111. ; Spon and Chamberlin, 123 Lib- 
erty Street, New York City, and the Weeden Toy En- 
gine Company, New Bedford, Mass. 

APPENDIX E 

Speed Indicators. — A Simple Way to Find the Speed 
of a Crankshaft. — To find the speed that a shaft or a 
wheel is turning is simple if you have a speed indicator. 
It consists of a spindle on which threads are cut forming a 
worm gear and this meshes with a gear to which the 
dial is fixed. 






6000EU P(?ATT Covswiy 
_ Gpan nnj.M >s3.u.SJl 




Fig. 84. A Speed Indicator 

By pressing the pointed end of the speed indicator 
against the center of the wheel or shaft the spindle turns 
the dial around and the number of revolutions can then 
be read off by timing it with a watch. 



INDEX 



Air pressure on piston, 6 

Airplane engine, 23 

Alcohol lamp, easily made, 29 

Alloys, 243 

Appendices, 247 

Atlantic type of locomotive, 

138 
Atmosphere defined, 189 
Atmospheres, steam measured 

in, 189 
Atmospheric engine, 6 
Automobile engine, 23 
Automobile, steam, 16 
Auxiliary parts of a horizontal 

steam engine, 88 

Babbitt metal, 235 

Ball governor, 120 

Bearings for shaft of model 
turbine, 40 

Bed plate for a horizontal 
steam engine, 70 

Bed Plate, mounting engine on 
the, 86 

Bed, setting engine on its, 86 

Beighton, Henry, 9 

Bell frame for locomotive bell, 
142 

Bell for a locomotive, 142 

Beveled gears, 229 

Blades, action of steam on tur- 
bine wheel, 43 

Blades, making steam turbine, 

33 
Boil, how water is made to, 185 
Boiler, a %2 h. p. vertical tube, 
A simple iron, 92 



Boiler — continued 

Back tube sheet for locomo- 
tive, 147 

To calculate heating surface 
of a, 197 

Connections, 105 

Crown sheet for a locomo- 
tive, 147 

A good copper, 102 

Firebox of, 97 

Firebox sheet for, 95 

Fittings for, 106 

Fittings for a locomotive, 150 

Front tube sheet for locomo- 
tive, 145 

Furnaces, burners for, 99 

Horsepower, 196 

How to calculate the size of 
a, 196 

How to test a, 107 

Locomotive, 140 

Safe way to operate a, 109 

Safety valve for, 116 

Seamless copper tube for, 95 

See steam boiler 

Shell of locomotive, 141 

Smoke box, 97, 104 

Smoke box sheet for, 95 

Smokestack for a locomo- 
tive, 142 

Steam dome for a locomo- 
tive, 142 

Steam gauge for, 130 

Steam in the, 189 

Steam injector for, 126 

Tubular, 140 

Tubes for locomotive, 148 



253 



254 



Index 



Boilers, dimensions for small, 

251 
Making small, 91 
For model engines, 250 
Safety valves for, 116 
Vertical tube, 250 
Whistles for, 113 

Boiling, what it means, 186 

Boulton and Watt, 193 

Book of electricity, 174 

Bourdon steam gauge, 131 

Branca's engine, 3 
Impulse turbine, 43 

Brass, 246 

Buffer beam of locomotive, 161 

Bunsen burner, 226 

Burners for boiler furnaces, 97 

Burner, kerosene, 100 



Cab for locomotive, 174 

Calibrating the dial of a steam 
gauge, 135 

Caloric engine, 20, 199 

Cardboard model of locomo- 
tive, 154 

Cast iron, 244 

Casting an engine cylinder, 72 

Castings for boilers and en- 
gines, 251 
For the Corliss engine, 249 
For force pumps, 251 

Castings for engines, 247 
Finishing engine, 72 
For a model engine, 62 
For oscillating engine, 249 
For safety valves, 252 
A steam chest, 75 

Cawley and Newcomen's en- 
gine, 7 

Central flue boiler, 104 
Flue steam boiler, 12 

Centrifugal force, 120 
Governor, 12, 120 



Clermont, Fulton's paddle 
wheel steamboat, 15 

Cogwheel locomotive, 16 

Compressed air engine, 20 

Compression stroke, 239 

Condensing engines, 190 

Condensing steam, 8 

Connecting rod bearing for 
steam engine, 81 

Connecting rod for a steam en- 
engine, 80 

Connecting rods of locomo- 
tive, 166 

Connections for boiler, 105 

Copper, 245 

Copper boiler for a small en- 
gine, 102 

Corliss engine, 249 

Counterbalance weight, 164 

Coupling rods for drive wheels, 

165 

Cowcatcher for locomotive, 173 

Cradle, engine truck of loco- 
motive, 160 

Crank for a horizontal steam 
engine, 70 

Cross-head guide block for 
steam engine, 78 

Cross-head guide for a hori- 
zontal steam engine, 70 
Of locomotive, 157 
For steam engine, yj 

Crown sheet for locomotive 
boiler, 147 

Cylinder castings, 248 
Casting an engine, 72 

Cylinder heads for a horizontal 
steam engine, 68 

Cylinder of a horizontal steam 
engine, 66 

Cylinders of locomotive, 157 

Dead centers of an engine, 90 
De Laval's steam turbine, 18 



Index 



255 



De Laval's steam turbine — ctd. 

Model, 30 
Development of the steam boil- 
er, 12 
Drawing plans for an engine, 64 
Drawing tools you need, 62 
Driving wheels locomotive, 164 
Ductile defined, 245 

Ebullition, 185 

Eccentric for a horizontal 
steam engine, 70 

Eccentric rod for a steam en- 
gine, 84 

Eccentric for a steam engine, 

83 
Electrolysis, 185 
Energy, heat a form of, 185 
Of motion, 187 
At rest, 187 
Engine, airplane, 23 
Assembling a crankshaft of 

a gas, 233 
Assembling a gas, 235 
Atmospheric, 6 
Automobile, 23 
A y 8 h. p. gas, 214 
Bed of a gas, 235 
Branca' s impulse, 18 
Branca's steam, 3 
Caloric, 20 
Cam and camshaft of a gas, 

228 
Camshaft bearings of a gas, 

227 
Castings, cylinders, 248 
Castings, finishing, 72 
Castings, horizontal, 247 
Castings, model, 247 
Castings for oscillating, 249 
Castings of type metal, 62 
Compressed air, 20 
Connecting pipe for a hot air, 

205 



'Engine — continued 

Connecting rod of a gas, 230 
Connecting rod of a hot air, 

202 
Crankshaft and crank for a 

hot air, 206 
Cylinder of a gas, 216 
Exhaust valve mechanism of 

a gas, 220 
Expansion cylinder of a hot 

air, 200 
Firebox for a hot air, 208 
The first, 1 
The first real, 10 
Fittings, where to buy, 252 
Flywheel and pulley of a gas, 

236 
Four cycle gas, 23 
Fuel mixture for a gas, 238 
Hero's reaction, 18 
Hero invents the steam, 2 
Gas and gasoline, 21 
Hot air, 20, 199 
Works, how a gas, 238 
Works, how a hot air, 210 
Igniter for an, 223 
Inlet and exhaust valves of 

a gas, 218 
Making a crankshaft for, 231 
Making a hot air, 200 
Newcomen's and Cawley's 

steam, 7 
Oiling a gas, 236 
Otto gas, 240 
Papin's piston steam, 5 
Parts of a gas, 216 
Parts of a hot air, 200 
Parts, mould of, 72 
Piston of a gas, 230 
Piston rod of a hot air, 202 
Power connecting rod for a 

hot air, 204 
Power cylinder of a hot air, 

203 



256 



Index 



Engine — continued 

Power piston for a hot air, 
204 

Self-acting, 8 

Standards for a hot air, 205 

Steam, 24 

Steam in the, 190 

Timing gears of a gas, 229 

To operate a hot air, 210 

Transfer piston of a hot air, 
201 

Truck frame, 160 

Walking beam, 7 

Watt's double acting, 11 

Watt's rotary, 9 
Eolipile, Hero's, 2 
Eolus, god of the wind, 2 
Ericsson hot air engine, 20 
Exhaust stroke, 238 
Expansion of steam in turbine 
nozzle, 44 

Fire box for boiler, 105 

Of boiler, 97 

Grate of, 98 

Sheet of boiler, 95 
Fire tubes, 13 

Firetube boiler locomotive, 16 
Fitch's steamboats, 14 

Steam packet, 14 
Fittings for boiler, 106 

For a locomotive boiler, 150 

For model engines, no 

Where to buy engine, 252 
Fluxes, 247 
Flyball governor, 120 
Flywheel of engine, 11 

For a horizontal steam en- 
gine, 70 

Momentum of, 215 

For a steam engine, 85 
Force pumps, castings for, 251 
Fuel mixture for gas engines, 
238 



Fulton's Clermont, paddle- 
wheel steamboat, 15 

Fulton's first steamboat, 15 

Furnace for oscillating cylin- 
der steam engine boiler, 58 

Fusible alloy, 244 

Gallipoli oil, 247 
Gas burners, 99 

Denned, 188 
Gas Engine, 21 

A y 8 h. p., 214 

Assembling the, 235 

Assembling the Crankshaft 
of a, 233 

Bed of a, 235 

Cam and camshaft of a, 228 

Camshaft bearings of a, 227 

Connecting rod of a, 230 

The cylinder of a, 216 

Exhaust valve mechanism of 
a, 220 

Flywheel and pulley for a, 
236 

Four cycle, 23 

Fuel mixture for, 238 

How it works, 238 

Igniter for a, 223 

Inlet and exhaust valves, 218 

Invention of the, 21 

Lebon's, 22 

Lenoir's, 22 

Making a crankshaft for a, 
231 

Oiling a, 236 

Otto's, 22, 240 

Parts of a, 216 

Piston of a, 230 

Timing gears of a, 229 
Gasoline engine, 21 
Gears, reduction, 18 

For turbine reduction, 41 
Governor, centrifugal, 12 

For steam engine, 120 



Index 



257 



Grate of firebox, 98 

Gauge, steam, for boiler, 130 

Water, for boiler, 136 
Gun metal, 243 
Gyroscope, toy, 31 

Hanger, saddle and pedestal 

for locomotive, 144 
d'Hautefeuille gas engine, 21 
Headlight for locomotive, 174, 

274 

Of a locomotive, 154 
Heat a form of energy, 185 

As kinetic energy, 187 

Latent, 187 

As potential energy, 187 

What it does to water, 184 
Heating surface, 13 
Hedley's locomotive, 16 
Hero of Alexandria, 1 
Hero's steam boiler, 12 

Reaction engine, 18 

Reaction turbine, 43 
Horsepower, boiler, 196 

How to calculate, 194 

Defined, 193 

Indicated, 196 

And work, 192 
Hot air engine, 20, 199 

Connecting pipe for a, 205 

Connecting rod of a, 202 

Crankshaft and crank for a, 
206 

Expansion cylinder, 200 

Firebox tor a, 208 

How it works, 210 

Making a, 200 

Parts of, 200 

Piston rod of a, 202 

Power connecting rod for a, 
204 

Power cylinder of a, 203 

Power piston for a, 204 

Standards for, 205 



Hot air engine — continued 
To operate the, 210 
Transfer piston of a, 201 

Horizontal steam engine, 61 

Hydrogen, 182 

Hydrostatic paradox, 127 

Igniter of a gas engine, 223 
Impulse engine of Branca, 4, 17 

Turbine of Branca's, 43 
Indicated horsepower, 196 
Initial pressure of steam, 44 
Injector, steam, 126 

Steam, how it works, 130 
Invention of the locomotive, 16 
Isometric perspective, 64 

Keeping up with your motor 

car, 223 
Kerosene burner, 100 
Kinetic energy, heat as, 187 

Lamp for oscillating steam en- 
gine boiler, 59 
Latent heat, 187 
Lebon's gas engine, 22 
Lenoir's gas engine, 22 
Lever safety valve, 116 
Link valve gear, how it is 
made, 168 

How it works, 179 

Locomotive, 167 
Liquid fuel burners, 99 
Locomotive, Atlantic type of, 
138 

Bell for a, 142 
Locomotive boiler, 140 

Back tube sheet for, 147 

Front tube sheet, 145 

To calculate heating surface 
of a, 197 

Crown sheet for, 147 

Fittings for, 150 

Steam dome for a, 142 

Tubes for, 148 



258 



Index 



Locomotive, cab for, 174 
Cardboard model of a, 154 
Connecting rods for, 166 
Cylinders, steam chests and 

cross-head guides, 157 
Dome for a, 142 
Driving wheels, 164 
With firetube boiler, 16 
Headlight, 154 
Headlight for, 174 
Hedley's, 16 
How it works, 176 
Invention of the, 16 
Link valve gear for, 167 
Link valve gear, how it 

works, 179 
Murray's, 16 
Parts of a, 140 
Parts of the engine, 156 
Pilot or cowcatcher for, 173 
Saddle, pedestal and hanger, 

144 
Sandbox for a, 142 
Scale drawings of, 139 
Setting frame on truck 

wheels, 163 
Shell of a boiler, 141 
Side on coupling rods, 165 
Smokestack for, 142 
Steam pipe and throttle 

valve, 146 
Stephenson's, 16 
Stephenson's Rocket, 16 
Tender, 175 

And tender, finishing, 176 
Trailing wheels for, 173 
Trevithick's, 16 

Major chord defined, 150 
Malleable defined, 245 
Metals, useful, 244 
Metal working tools, 63 
Mica for gas engine igniters, 
224 



Miller and Symington's steam- 
boat, 15 
Mitis metal, 244 
Model De Laval steam turbine, 

30 
Model steam turbine, 24 
Model steam turbine, tools 

needed to make, 32 
Molecules of matter, 185 
Momentum of a flywheel, 215 
Moulding engine parts, 72 
Mounting the engine on the 

bed plate, 86 
Mounting the wheel of model 

steam turbine, 41 
Muriatic acid solution, 247 
Murray's locomotive, 16 

Newcomen and Cawley's en- 
gine, 7 
Newcomen and Watt, 192 
Nozzle works, how a steam 
turbine, 44 
Making a model steam tur- 
bine, 35 

Oil for gas engine, 236 

Oscillating cylinder steam en- 
gine, 45 
See Steam engine oscillating 
cylinder 

Otto's gas engine, 22, 240 

Otto, gas engine inventor, 240 

Oxygen, 182 

Pattern making, 241 

Patterns for a horizontal steam 

engine, 65 
Papin's piston engine, 5 
Parsons' steam turbine, 18 
Pedestal, saddle and hanger 

for locomotive, 144 



Index 



259 



Pewter, 243 

Pillow blocks for a horizontal 
steam engine, 70 
For a steam engine, 86 

Pilot, or cowcatcher for loco- 
motive, 173 

Pipe and Fittings for engines, 
no 

Piston engine, Papin's, 5 

Piston for a horizontal steam 
engine, 69 

Piston and piston rod for 
steam engine, j6 

Packet, Fitch's, 14 

Pop safety valve, 118 

Potential energy, heat as, 187 

Potter's self-acting engine, 8 

Pounds, steam measured in, 
189 

Power stroke, 239 

Pressure of steam, initial, 44 

Propeller driver steamboat, 15 

Pump, steam force, 123 

Radius of a circle defined, 149 
Reaction engine of Hero, 3, 18 
Reaction turbine of Hero, 43 
Rectangular steam boilers, 12 
Red brass, 243 
Reduction gears, 18 

For model steam turbine, 41 
Resin, 247 
Rocker arm for steam engine, 

79 

Rocket, Stephenson's locomo- 
tive, 16 

Rotary engine, Watt's, 9 

Saddle, pedestal and hanger 

for locomotive, 144 
Safety valves, 116 

Castings for, 252 
Sal ammoniac, 247 
Sandbox for a locomotive, 142 



Scale drawings of locomotive, 

139 
Seamless copper tube for boil- 
er, 95 
Self-acting steam engine, 8 
Setting the engine on its bed, 

. 87 

Setting locomotive frame on 

truck wheels, 163 
Shell of a simple iron boiler, 92 
Shrinkage rule, 242 
Side on coupling rods for loco- 
motive, 165 
Slide valve for a horizontal 
steam engine, 69 
And slide valve stem for 
steam engine, jj 
Smoke box for boiler, 104 
Of boiler, 97 
Sheet for boiler, 95 
Smokestack of a locomotive 

boiler, 142 
Speed of a crankshaft, how to 

find, 252 
Speed indicators, 252 
Spring safety valve, 118 
Standard brass, 243 
Steam automobile, 16 
Steamboats, the first, 14 
Fulton's first, 15 
Miller and Symington's, 15 
Propeller driver, 15 
Steam boiler, 24 
Steam in the boiler, 189 
Steam boiler, central flue, 12 
Development of, 12 
Furnace for oscillating cylin- 
der engine, 58 
Hero's, 12 
Making a toy, 24 
For oscillating cylinder en- 
gine, 5 
Rectangular, 12 
Tubular, 14 



260 



Index 



Steam chest, casting a, 75 
For a horizontal steam en- 
gine, 69 
Of locomotive, 157 
Steam, condensing, 8 
Steam dome for a locomotive 

boiler, 142 
Steam engine, a %4 h. p., 61 
Assembling an oscillating 
cylinder, 53 
Steam engine boiler, lamp for 

oscillating cylinder, 59 
Steam engine, condensing, 190 
Corliss, 249 
Dead centers of a, 90 
Drawing plans for a, 64 
Fittings for, no 
Governor for, 120 
High pressure, 190 
How to calculate h. p. of 

your, 194 
How to run oscillating cyl- 
inder, 59 
How it works, 89 
Steam engine works, how an 

oscillating cylinder, 59 
Steam engine of locomotive, 

156 
Steam engine, an oscillating 
cylinder, 45 
Parts of an oscillating cylin- 
der, 47 
Parts for a %4 h. p., 65 
See Engine 
, A simple piston, 45 

Stopcocks and taps for, 112 
Throttle valve for, 120 
Tools you need to make a, 

62 
Tools needed to make an os- 
cillating cylinder, 46 
Where to buy materials 
for oscillating cylinder, 
50 



Steam in the engine, 190 

Expansive power of, n 
Steam force pumps, 123 
Steam, getting up, 186 

The giant power, 182 
Steam gauge, 189 

For boiler, 130 

Bourdon, 131 
Steam, how it acts, 189 

How it is measured, 189 
Steam injector for boiler, 126 
Steam locomotive, see Locomo- 
tive 
Steam power plant, parts of a, 

25 
Steam pressure, about, 188 
Steamships driven by steam 

turbines, 19 
Steam turbine, 5 
Bearings, model, 40 
Blades, how to form model, 

33 
De Laval's, 18 
How to run the toy, 29 
Model, De Laval, 30 
Model, reduction gears for, 

Modern, 17 
Multiple, 19 

Nozzle, how it works, 44 
Nozzle, making a model, 35 
Of Parsons, 18 
Single wheel, 18 
On steamships, 19 
Speed of model, 41 
Two simple, 24 
Wheel case, model, 37 
Wheel, mounting the, 41 
Wheel, making a model, 32 

Steam turbine works, how 
model, 43 

Steam whistle, 113 

Steam, what it is made of, 182 

Steel, soft, 245 



Index 



261 



Stephenson link reversing gear, 

168 
Stephenson's locomotive, 16 
Stirling hot air engine, 20 
Stopcocks and taps, 112 
Suction stroke, 238 
Swage and Peening tools, 96 

Tallow, 247 

Taps and stopcocks, 112 

Temperature of water, 186 

Template for turbine blades, 33 

Tender of locomotive, 175 

Testing a boiler, 107 

Throttle lever for locomotive, 

153 
Throttle valve, II, 120 

For locomotive boiler, 146 
Timing gears of a gas engine, 

229 
Tools you need, 62 
Toy gyroscope, 31 
Toy paddlewheel engine, 24 
Toy steam boiler, 24 
Toy turbine, how to run the, 29 
Toy turbine wheel, 27 
Trailing wheels for locomotive, 

173 

Trevithick's locomotice, 16 

Truck frame of locomotive, 160 

Tubular boiler, 14, 140 

Turbine, steam, see Steam tur- 
bine 

Turbine wheel for toy turbine, 
27 

Type metal castings for an en- 
gine, 62 



Vacuum chamber, 190 
Vacuum in cylinder engines, 

6 
Valve, spring and lever safety, 

116 
Valve stem and bearing for 

steam engine, 80 
Valve, throttle, 11 
Vapor, defined, 188 
Venice turpentine, 247 
Vertical tube boiler, 91 
Vertical tube boilers, 250 
Vibrations of matter, 185 



Walking beam engine, 7 
Water, to decompose, 185 

Formula for, 183 
Water gauge for boiler, 136 
Water, how it is formed, 184 

How it is made to boil, 185 

Temperature of, 186 

What heat does to it, 184 

What it is made of, 182 
Watt, 193 
Watt's double acting engine, 

11 
Watt, James, 9 
Watt and Newcomen, 192 
Watt's rotary engine, 9 
Wheel case for model steam 

turbine, 37 
Whistle, steam, 113 
Wood working tools, 63 
Work and horsepower, 192 

Time and effort, 193 

Unit of, 193 



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